Recollect how many times have you have tried to stop sending an email or regretted after sending it? To overcome that, Google Labs for GMail has launched Mail Goggles. The new Labs feature by default activates only late nights at the weekend, the possible time when you need it the most.

To enable this feature -- click on the Labs button in the GMail account and then enable the Mail Goggles feature. To adjust the time frame, visit the General settings tab in the Settings and adjust the favorable time period for which you wish to enable the Mail Goggles feature. One can also set the difficulty level for the problems higher level for more difficult problems.

Whenever you try to send any email late night during weekends, five math problems show up after send button is clicked and you have to solve those five problems in limited time frame to prove that you are in right frame of mind.

Alternatively, this feature can be used even during the day time when mass-mails are required. Wear your Mail Goggles and play safe before you get a black eye for sending wrong mail to the wrong person.

Source: Gmail Blog