When they rub their eyes that means they don’t care at all about what you’re saying, and that noise it makes, that squelch, is really gross. Even when I have an eye itch I’ll feel self-conscious about that hideous noise if anyone’s nearby.
When they put a finger in their ear and twist it, that means that they’re judging you, usually harshly, even if they’re smiling.
A head scratch means they’re thinking, but the farther back the scratch the more self-conscious they are, not about thinking, but in general.
Nose-picking can sometimes be an itch but repeated nose picking means that they’re comfortable around you and with themselves, too comfortable.
Wedgie picking is surprisingly passable, disgustingly, especially during the summer, when girls wear skirts.
Moving between one eye and the other during conversation usually means they’re not thinking about what you’re saying, they’re thinking about what eye they’re looking into. The right is the one most people prefer, and as a result many have one stronger eye.
Any other weird body languages you can think of?