I used to be cripplingly shy, and have absolutely terrible self-confidence. Like the non-existent kind. In the last few years I've gotten a lot better. Especially in the shy department. In fact, I love telling recent acquaintances that I used to be quiet and didn't talk. They're speechless!
And in the self-confidence department, I'm pretty damn good too. I don't think I'm capable of everything, but I don't think I'm incapable of everything. I think I've struck a pretty good balance between realism and optimism in terms of what I'm capable of.
There's one area, though, where I have absolutely zero confidence, and that's when it comes to men. There are a lot of reasons for it. My weight, for one: I know there are men who dig the fatties, but I think there are more who don't. Then there's my relationship history: totally dysfunctional. And my families' relationship histories: not a successful marriage on either side. There's my quirks: I have three cats, I don't want kids, I don't want to get married. There's my feelings on sex: not going to happen until a long time in to a relationship. There's my enjoyment of being alone: I love living alone, I love having space to myself, and I love not having to tell anyone where I'm going to be every minute of the day.
I'm sure that somewhere, maybe even close by, there's a man I'd be attracted to who likes fat girls, doesn't want marriage or crotchspawn, loves cats, is willing to be celibate, can respect my privacy, and is patient enough to deal with me working through my unhealthy relationship issues. But I wouldn't even know where to start to look for him. And I certainly don't know if the cute regular customer at work who inspired this post fits. Or how to flirt with him to try to find out. Or if I'm even really ready to try.
I can relate completely to the first two paragraphs. I think by nature I am a very introverted person who has learned how to be extroverted when it is requred. I still consider myself generally shy.
I've also been single most of my adult life. I've had long term relationships, but it takes approximately 2 years for me to become completely intollerable based on past experience. I have to say that of all the things you listed as impediments to a relationship, you are missing the biggest one. You seem completely comfortable with your single life as it is. It will be incredibly tough for any relationship to be worth it if things are perfect as they are. Dating is a pain, but it is the way you go about auditioning someone to let into your life. If you don't see the benefit to filling that role, then it isn't worth the hassle.
If you decide it is worth it, then the other things can fall into place. You might find yourself more willing to look past your issues once you see the benefits of having someone in your life. If you see no benefit to it, then it is probably not worth the bad karma of stepping into the dating pool.