Shyness, laziness, and pretty much all the other stuff everyone who posted in this thread have.
Oh, and loneliness. But seeing how all of you are makes me feel less lonely. But since I don't know any of you in real life(Heck, I'm too lazy to even post here that I don't even know any you of in MT) I feel lonely again.
Oh, and also constantly contradicting/criticizing/justifying anything I just think of or think of doing. That's a character flaw, right? Not? Maybe?