Ever since Gmail introduced Gmail Labs, the face of Gmail changed forever. With Gmail Labs, the developers at google can skip all the beurocratic redtape and launch new Gmail additions on the fly. As a result there have been many additions to Gmail adding new features and modifications to current features which have made Gmail really a pleasure to use. Now there is another addition to the the Gmail Labs features.
But GMail now has just the answer - Undo Send. You have a 5 seconds grace period after the clicking of the "Send" button to stop the e-mail and send it back to the drafts. This really would turn out to be a life saver to many people.
The option isn't turned on by default and as such you have to activate it. To activate it, log in to gmail, click on settings on the top right of the page. select the labs tab and scroll down to the undo send feature. Enable it by selecting the enable radio button and scroll down and save your settings. And viola - thats it