As this is one of the oldest trick but many of us doesn't know about this feature so i thought of re-posting it in this blog.
we can undo the sent mail. simply, u have sent an e-mail to a wrong mail id, with this feature, we can un send the mail easily.
the procedure is as follows:
you need to go to Settings -> Labs -> Undo Send, and select ‘enable’.
Once this feature is activated, you will see a new ‘Undo’ link appear on every sent mail confirmation. Clicked this link will take you back to the composing window allowing you to cancel the delivery or modify the message.
This feature was added by g mail in 2009 itself but many still doesn't know about this..
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