I have a hard time talking to a person if:
1. They're way cooler and more acomplished than me
2. They are older than me
3. They look condenscending and would get annoyed at me
4. It's a cute girl I like
Often these overlap. Essentially I don't come and talk to people out of fear of rejection or that they'd get pissed at me, and other times I just don't bother, because I know my tastes and topics of choice are so painfully esoteric. I went through GREAT LENGHTS in school to avoid meeting and talking to people because I know I'd just do them a disfavour by merely existing. If I can not relate to you, I just don't want to bother with you. Because of my lack of proper communication(even within my own family, I just don't talk to anyone because I relate to no one in my family), my language skills are nill, but I am a prolific writer and artist, somehow. It's the old introversion = rich mental world shit, which I am grateful for, and part of the reason why I like Tomoko is that she has a rich mental world too.
I haven't had a single true friend until I got 17 years of age. That's when I really started meeting people I could truly relate to and talk unbridedly about anything and they'd get it. Some of them are even abroad, and I've lived through the experience of meeting three of them in person, and it was a blast and I can talk to them so easily! I guess the moral of the story is no matter how hard society presses you, find and stick to your own kind. Rejects are much more interesting, intelligent and inspired people than the common folk anyway.