Most Helpful Guy
Sorry you feel this way - I would encourage you to take a break first but if you must leave - Go to your profile page then Settings and down bottom there is a button to click to deactivate your account.
Most Helpful Girl
To cancel your account, hover over you username and click on "Settings." then scroll down and you should see on the right side "To cancel your GirlsAskGuys account, click here" so just do that and follow the instructions to cancel your account.