There's multiple reasons. Anxiety used to be a big problem but since I figured out that alcohol is a cure for that, its been less and less of an issue.
Finding someone that I connect with is difficult too. I'm a geeky super-liberal living in a very small redneck town. I'm not interested in one night stands or doomed from the start relationships but that seems to be the only things I can find. Also I have a perception problem where I see women my age and they seem much more mature than me with kids and careers and I see woman younger than me as immature brats that have no respect for anything.