Why do I like men who do not like me back?

I have noticed over the years that I attract myself to certain men. Sadly, many of them do not reciprocate the feelings. I guess I pick up signals that make me think they like me, but eventually do not. Maybe I am someone who they can get attention from...I don't know. Plus, my physical and personality characteristics don't seem to match with theirs, so I can understand why they do not like me. I have some assumptions as to why, but I won't mention it here. Yet, I do have another dilemma.

There are men that like me and I do not like them back. It's not like I have a lot of guys chasing me given I am not around many, but the few that do have characteristics that I am not attracted to. I don't think I am a snob and some tend to be too aggressive. I have recently learned that I am shy and want to run away from them. I guess the way I am going, I will probably never date or get married.

Some things to also consider: I used to be very aggressive in chasing after men, but have learned a very harsh lesson that most men do not like to be chased. I just graduated from a university where I was around students that were not be attracted to me due to age, race, body type perception. On a positive note, I am living in a new city, so this could be in my favor. I am not into dating online given that's what I did during my first 5 years of dating (I started when I was 18) and want to learn how to market myself without the help of a computer.

Please do not think I am weird. Just trying to better understand myself. I appreciate any advice. Thanks!