No more accidentally sending that killer turkey burger recipe to your boss when it was intended for your aunt. How embarrassing! Was your strongly worded email to the neighbourhood association about Mr Vanlandingham's obnoxious mailbox colours a bit too strongly worded? Just click undo and delete all those what the fudges and holy shoots. Problem solved!
So how do you enable Gmail's undo feature? Go to the little cog icon in the upper righthand corner and select "Settings." About a third of the way down the page you'll see the "Undo Send" section. You can choose between 5, 10, 20 and 30 second windows of unsendability. Make sure you hit "Save Changes" at the bottom and you're all set.
Then, the next time you hit send on an email that you probably shouldn't have, you've got precisely that many seconds to change your mind and hit the undo button at the top of the page. Decide after 31 seconds that maybe you shouldn't call your sister's new boyfriend a dull, shit-breathing knobhead for spilling his entire Zima over your head at last weekend's barbecue? Well, you're out of luck in that case, friend. Technology can't solve all your problems.