I move my hands when talking quite a bit, especially when I'm excited or being really descriptive, but I don't notice it much when other people do it. It's usually very exaggerated for effect on TV shows and cartoons, which is possibly the reason my own gesturing is sometimes exaggerated. I read in a book about animation that when characters point they never just point, they always do this dramatic sweep with their arm first. Most human language is nonverbal so it's no wonder Aspies get confused a lot by what people are trying to "say".