Well it is probably easier to hook up with a girl that is clingy and/or psycho. Nobody else really wants to date them and they hook up or obsess with the first guy to give them any attention. You aren't going for the challenge of finding that girl you want and instead hooking up with these clingy girls.
It's actually kind of weird because the girl I'm seeing now isn't that clingy, especially compared to my prior relationships. We talk or see each other every day but in the past things were so much worse, I'm honestly not used to it. For the most part, it's great.
That you are a distant person, afraid to get too close.
And that you need to be validated constantly to feel like you are worthwhile.
The damaging part of that is, that eventually the clinginess dies out...the massive ego trips given by said clingy girls thins away to nothing, and in the end you are left empty in the relationship that once had you feeling so high.