8. They Leave In The Middle Of The Night
While most people believe that leaving in the middle of the night is a common sleaze move (it generally is); it also means that the sex could be bad enough that the person does not want to have to deal with you (or the awkwardness) in the morning. Nothing is worse than waking to find whoever you fooled around with the night before has gone missing and did not even think to leave their number. The sex must be pretty bad for someone to put so much effort into sneaking out of a bed, and tip toeing out your door leaving it unlocked and making you vulnerable to predators.