Mine would probably be my self confidence. I have next to none and always think he doesn't like me, is going to find someone better, along with that I struggle with depression and my anxiety also doesn't help when I over think things, combine that with my lacking confidence and I'm of thinking he's about to start a new relationship and have a family with say, a girl he works with or something. However I don't let him know I think this, but some times something will slip.
Outside of relationships, as far as dating goes, my biggest hang ups were arrogant guys trying to tell me what to do, doesn't sit well with me so maybe I was too strong willed at times.
Also being too comfortable doing my own thing and having my own life as well, some guys expect you to give up everything for them and to morph into one person just because you're dating them, I can't/won't do that.
Lack of communication. I like to communicate with my partner, not know where he is 24/7 or anything. But if we had plans, it'd be nice if he sent a text letting me know he'd be late or something. I also think it's cute when he calls (hands free) on his way home from work, or calls me at night before bed.
The guys I dated where very much into calling or texting in the beginning, a bit too much actually. Once they stop communicating, I get a bit irritated. I tried to let it go, but it's disrespectful to me. Once I start losing respect for them, I don't want to be around them any more and I detach.
Probably my inability to let them know how important they are to me... no, that's a lie. My inability to genuinely value one human over another. My inability to pretend my life would be over if they left me and my refusal to pretend I'd never be happy again.
I'm a bit quirky and out there (a lot of my friends call me a hipster for some reason). And while this means I have amazing girlfriends, it also seems to means guys are often scared off. The ones I do attract are often know-it-all assholes who have to show how smart they are all the time and can't have a decent conversation or are rather one dimensional. In addition to that, I'm not particularly pretty, am really athletic (rugby is life lol), very driven (academically), passionate (about a lot of social issues, interests and hobbies), and rather independent (I like my "me time"). Most guys just aren't interested in that, it would seem, and often don't (never) approach me and only approach my friends (who I can admit are prettier lol).
Not understanding my window of making a move/ what move I even want? Do I just want sex? Do I even want to get involved with this girl as hot as she is? I never know if , I want a girlfriend or if I just want female company.. So I feel like I pursue half ass.. I never go all out , I'm hot and cold... I might text you here , shoot you a date request there.. If the answer isn't up to my exception I usually ghost for a bit (not intentionally) but I just forget about texting the girl.. then out of the blue , I might shoot some texts to 6-7 different girls (some are happy to hear from me) I usually spit some funny cocky game get them excited.. I may get one date.. or none.. or get a girl to accept only to flake on me rinse repeat.. I guess to some it up, I really just half ass interactions and my intentions are never really clear.. I am not direct because generally I am unsure of what I want from girls.