Creator: Enrico Tartarotti · Published: 2025-10-17 · Length: 14:30 · Watch on YouTube

Discover how Gmail's undo send, CTRL+Z, Google Docs, and Instagram are all secretly designed around human mistakes. (from the video description)

Enrico walks through the hidden design and engineering that lets people keep making mistakes without paying for them, and argues that the tools we use are built for imperfection rather than perfection. Sponsored by Notion (Notion Agents). Written and produced by Enrico Tartarotti; editing by Seequence Studio. (The auto-captions mishear several names: "Ro" and "Arico" for Enrico, "Michael Leget" for Michael Leggett, "Larry Tesla" for Larry Tesler, "Kevin Cyester" for Kevin Systrom, "things free" for Things 3 and "Fitz's law" for Fitts's law. The corrected names are used below.)

1) Detailed outline

[0:00] Gmail's Undo Send

• You send an email to your boss before logging off for the weekend, realize it has the wrong attachment, and hit Undo Send. How is that possible?
• In 2009 Michael Leggett at Google sent an email to the wrong Larry. Embarrassed, he wondered why, if we use Ctrl+Z all the time, we can't undo an email.
• The trick: when you hit send, the email doesn't go anywhere. It sits in a hidden queue for 5, 10, 20 or 30 seconds (adjustable in settings), and only then does Gmail send it for real.
• That artificial delay is technically a flaw, since every Gmail message arrives 5 to 30 seconds late, but Google considers it so important that you can't turn it off.
• Thesis: tech is not designed for perfection, speed or aesthetics. It's secretly designed to make up for how humans fail, and once you see it, it's everywhere.

[1:17] What Ctrl+Z really does

• After a staged "let me go… Ctrl+Z" retake, Enrico explains that undo hides far more complexity than it seems.
• Undo keeps a history of every version you create, like a stack of plates; hitting Ctrl+Z removes the top plate rather than deleting anything.
• If you undo and then type something new ("Frodo Baggins" over "you're my only hope"), the old branch of plates is gone. A true undo would need a tree of every version branching out. Most programs don't do this, though some do.
• Storing every full version of a 1 MB book would fill gigabytes within minutes, so undo stores only the changes (edit these five characters at this position on this line).
• Add Google Docs-style collaboration: if you type "Obi-Wan Kenobi" where Sarah types "Frodo Baggins" and you both hit Ctrl+Z, whose change disappears? The answer is operational transformation, the synchronization technique Google uses for Docs, which comes with a whole technical paper.
• All that complexity exists so humans can keep making mistakes and undoing them, and so that when it works you never notice.

[3:10] Why it's Ctrl+Z

• Larry Tesler, credited with inventing undo in the 1970s, also invented copy and cut. As Enrico tells it, copy went to C, cut went to X because X suggests removing something, paste got V because P was too far away, and undo got Z, which "with some imagination" suggests going back and forth in time.
• Fifty years later, designers and engineers keep making undo not just better but more human.

[3:47] From correcting mistakes to preventing them

• Once designers realized humans need forgiveness built in, they asked: what if we prevent mistakes altogether?
• Old tech: one wrong character in a long terminal command and it simply refuses, with no hint of what's wrong.
• Microsoft Word's red zigzag underline tells you that you messed up so you can fix it yourself.
• YouTube search fixes a misspelling automatically but adds a subtle "did you mean" link in case you meant the original.
• ChatGPT and other AI chatbots understand "absolute garbage" input and even five minutes of rambling in voice mode. "We've gone from 'you made a mistake, let me fix it for you' to 'mistakes don't matter at all.'"

[5:11] Making deletion forgiving

• Deleting is the most dangerous action in tech. Forty years ago, a delete command pointed at / instead of a folder path would wipe the whole machine with no warning.
• The trash can put deleted files in a limbo you empty manually.
• Google Photos keeps deleted photos in the trash for 60 days so you don't have to remember to purge them, and Enrico says they're still recoverable for another 30 days after that.
• "We've gone from punishing mistakes to preventing them entirely."

[6:01] Subtle forgiveness in the details

• In the to-do app Things 3, typing June 31st (which doesn't exist) quietly becomes July 1st, with no error and no making you feel dumb.
• Button design: a button that fires the instant you touch it, with no feedback, feels wrong, especially for "Buy now" or "Submit." A better one shows visual feedback on press, fires only on release, cancels if you drag your finger off, and re-arms if you drag back. None of that is native; someone had to design it.
• Coyote time: in Mario, you can still jump a moment after running off a ledge. It's named after Wile E. Coyote hanging in midair before he falls. Games give you a few extra milliseconds because human reaction time isn't perfect, so the game pretends it is.
• Autosave: 20 years ago, forgetting Ctrl+S meant losing everything. Google Docs, Notion and Figma now save every change by default.
• "Mistakes are temporary, deletion is reversible, and your indecision is just part of the process."

[7:43] Designing for physical mistakes

• Right-click menus are genius because they appear right where the pointer already is. Fitts's law: the time to hit a target depends on its distance and size, so closer and bigger is easier.
• Submenus expose another human habit: people move diagonally toward the item they want, and that path leaves the menu and closes it.
• At Notion's San Francisco headquarters, their designers showed Enrico how Notion's menus stay open on a diagonal path, using math on the geometry between the pointer and the corners of the submenu.
• A Notion designer adds that clicking slightly off a checkbox still toggles it, "because it's just a tricky target and people are imperfect."

[9:03] Sponsor: Notion Agents

• Notion, which Enrico uses to manage his channel and his startup Flask, sponsors the video with Notion Agents: specialized workers that can take complex, multi-step actions across a Notion workspace and other tools.
• Examples: pulling together everything about a topic spread across Notion, Slack and mail; building an up-to-date attendee table linked to the emails and messages you got; reorganizing a project tracker as updates arrive; generating views, databases and boards for you.
• Agents also learn how you work by watching patterns (how you format meeting notes or tag sponsors) rather than from rules you write. Free to try via the link in the description.

[10:08] When design ignores imperfection

• In Spotify on desktop, clicking to expand the album view opens a panel far across the screen instead of near where you clicked. Your eyes and mouse travel across the whole screen, and it feels wrong because it violates Fitts's law.

[10:29] Betting on what users will do

• Sometimes the trick is exploiting the moments people don't make mistakes. Kevin Systrom, who worked on Gmail, explains in a clip that once you've typed your username, the odds you'll sign in are extremely high, so Gmail started loading your account in the background before you entered your password.
• Systrom later left Google and co-founded Instagram, using the same trick: the photo starts uploading while you're still on the caption screen, on the assumption you'll post it (and it's deleted if you don't). When you hit share, the progress bar seems to finish almost instantly.

[11:43] Tech that reads your frustration

• Old calculators sometimes cleared only the last operation on one press and everything on a second, so people smashed the clear button five times.
• Apple saw people shaking the mouse or trackpad to find a lost cursor and made the cursor grow huge when you shake it.
• Shake to undo on iPhone: shaking the device, a physical expression of annoyance, offers to undo your last typing.
• Optimistic updates in Flask, Enrico's video collaboration and creative feedback tool: saving a note normally means a round trip from browser to server and back, under a second but enough to feel slow. With optimistic updates the app assumes success, shows the change immediately and saves in the background, warning you only if it fails. That's why some apps feel snappy and others clunky: the frustration of slowness outweighs the need for 100% certainty before seeing a result.

[13:42] Conclusion

• "Your technology is lying to you": Ctrl+Z isn't undoing, Gmail isn't unsending, games help you cheat and delete isn't deleting.
• When Larry Tesler invented undo, he was declaring that humans have a right to make mistakes, that tools should forgive us, and that perfection shouldn't be a prerequisite for using technology.
• Teaser for the next video: why we get angry when Netflix raises its price by $2 but rush to buy a $1,600 iPhone every year, the story of how the price of our tech got broken.

2) Things mentioned

Undo, deletion and recovery features

• Gmail Undo Send (2009 origin; 5, 10, 20 or 30 second delay; can't be disabled)
• Ctrl+Z undo, plus Ctrl+C copy, Ctrl+X cut and Ctrl+V paste
• Undo stacks versus undo trees; storing changes (diffs) instead of full copies
• Operational transformation for real-time collaboration in Google Docs
• Terminal delete commands aimed at / (wiping a whole machine)
• The desktop trash can
• Google Photos trash (60 days, plus the extra 30-day recovery Enrico mentions)
• Autosave in Google Docs, Notion and Figma
• Apple shake to undo

Error correction and prevention

• Microsoft Word red squiggly spell-check
• YouTube search autocorrect with "did you mean"
• ChatGPT and other AI chatbots, including voice mode
• Things 3 silently turning June 31st into July 1st
• Press-and-release button behavior with cancel on drag-off

Interaction design and physical forgiveness

• Fitts's law
• Right-click (context) menus
• Diagonal-safe submenus in Notion (pointer-to-menu-corner geometry)
• Forgiving checkbox hit areas in Notion
• Spotify desktop's far-away album panel (a counter-example)
• Coyote time in Mario games
• macOS shake-to-find-cursor (the cursor grows when you shake the mouse)
• Calculator clear buttons

Performance tricks

• Gmail preloading your account after you type a username
• Instagram uploading photos in the background during captioning
• Optimistic updates (shown in Flask)

Products, companies and media

• Google, Apple, Microsoft, Meta and Instagram
• Notion and Notion Agents (sponsor), with Slack and mail integrations
• Flask (Enrico's video collaboration and feedback tool)
• Netflix and the $1,600 iPhone (next-video teaser)
• Pop-culture placeholder text: Frodo Baggins, Obi-Wan Kenobi and "you're my only hope" (Star Wars)
• Wile E. Coyote (Looney Tunes)

Places

• Notion headquarters, San Francisco

3) Biographies

Enrico Tartarotti

Italian-born YouTuber, designer and entrepreneur whose channel goes "behind the scenes of the design, psychology and stories behind the tech we use everyday." He founded Flask (flask.do), a video collaboration and creative feedback tool he uses here to demonstrate optimistic updates, and he writes and produces his videos, which Seequence Studio edits.

Michael Leggett

Google employee (Enrico calls him an engineer) whose embarrassing 2009 email to the wrong Larry led to Gmail's Undo Send, which started as an experiment and became a standard Gmail feature.

Larry Tesler (1945–2020)

American computer scientist who worked at Xerox PARC, Apple, Amazon and Yahoo and championed "modeless" interfaces. He's widely credited with cut, copy and paste, and Enrico credits him with undo and the Z, X, C and V shortcuts.

Kevin Systrom

Co-founder and former CEO of Instagram, which he launched with Mike Krieger in 2010 and which Facebook bought in 2012. Before that he worked at Google, including on Gmail. In a clip he explains how Gmail preloaded accounts and Instagram pre-uploaded photos to feel instant.

Paul Fitts (named only through Fitts's law)

American psychologist who in 1954 described Fitts's law, which says the time to reach a target grows with its distance and shrinks with its size. It's a core rule of interface design.

Wile E. Coyote

Looney Tunes cartoon character who runs off cliffs and hangs in midair before falling. Game designers named coyote time after him.

The Notion designers (unnamed)

Members of Notion's design team at its San Francisco headquarters who show Enrico the diagonal-safe submenu math and the forgiving checkbox hit area.