Ever wanted to retract an email just sent? I have! Several times I wished I could un-send an email, because seconds after clicking 'Send', I realize I forgot to attach or include an important recipient, etc.
So now you can! Turn on Undo Send in Gmail Labs under Settings, and you’ll see a new “Undo” link on every sent mail confirmation. Click “Undo,” and they’ll grab the message before it’s sent and take you right back to compose.
How awesome is that?