Not only am I misunderstood by others, but also by myself (ie. I don't understand myself). I don't think I'm unique in this... you grow, you learn. Of course, the situation is exacerbated by my ungated weirdness and excess energy.
Now for specifics:
1) Most people's first impression of me is that of a ditz/airhead or a nice quiet girl.
2) People assume all my comments are random. In fact, they're full of loose associations. It's called creativity, people!
3) People think I'm happy all the time (no surprise here).
4) They think I'm superficial (a combo. of 1 and 3).