“Sometimes I send messages I shouldn’t send. Like the time I told that girl I had a crush on her over text message. Or the time I sent that late night email to my ex-girlfriend that we should get back together. Gmail can’t always prevent you from sending messages you might later regret, but today we’re launching a new Labs feature I wrote called Mail Goggles which may help.”
The idea behind Mail Goggles is quite simple and effective: you can only send the email after having solved successfully several math problems
The default settings have Mail Goggles active only late night on the weekend. Needless to say, one can adjust the time frame in the General settings once he has enabled the feature.