I've been known to waltz with my eyes closed and all for myself, does that count? (Definitely introvert here. And for the longest time I felt much as blaisepascal describes, until I decided that my "proper" moves are so awesome that they'd fit into an "improper" crowd, too, and feel perfectly at ease after getting the vague idea of what the other folks are about.)

I also totally thought "proper and improper dancing... the kind with the lady on the right and on the left?"