Ah, I've been having similar feelings/issues over the last couple of years too. I felt like I was the only one who had these issues for a long time. I'm also starting to wonder if it is the "nice" factor too. An ex often tells me I'm the nicest person he's ever known but it seems he'd rather hang around with not-so-nice people.This puts me in the middle of confusion city! It's hard to be not-so-nice when you really are nice, genetically or something. I'm not sure how to judge who will be good or bad for me early on but I'm training myself to not be afraid of casting a friend/relationship aside if it really isn't working for me. As an adult it seems like new friends are few and far between but they come along eventually. Just keep moving forwards. It sounds like you really do know how to decide what is right for you in the long run. Just be yourself.