I'm finding a mini-streak of posts on my friendslist abut mistaken impressions and misconceptions interesting.
Some time ago I wrote a similar post, about things people thought about me that were incorrect - that I'm about five years older than I am, that I'm vegetarian and that I'm not Scottish, seem to be the main ones. I don't think those have changed significantly but I'd be interested to know what other perceptions you had of me which turned out to be wrong, and (again) what people seem to take for granted about you which is inaccurate.