Here's another scary one. When you're at your weakest point, a person begins to use careful manipulation to slowly push your self esteem down and make you feel horrible until that person has you in a position where you feel it's him or nobody. In the end he turns out to be nothing but a psychopathic, egocentric, narcissistic asshole, who cares nothing for people who aren't himself. Then, when you come to your senses and end the minutes-long relationship, he starts guilt tripping you and becoming a total douche nozzle to not only you but your friends as well.
I guess in the end it wouldn't matter, it'd just be another hambeast to try and forget about.