Trust good ol' Google to do it again.
After making sure you dont send off emails after a night of getting wasted, or those you'd regret later - by making you answer a simple mathematical question, Google's gone a step ahead and engaged the "5 second rule".
The Undo Send feature in Gmail Labs will enable an “Undo” link on every sent mail confirmation. Clicking on “Undo” - in case you realize that you've sent the mail to the wrong person - will stop the mail from being sent and take you right back to compose.
This feature can't pull back an email that's already gone; it just holds your message for five seconds so you have a chance to hit the panic button.
