Not sure if I did anything wrong here, but it seems highly feasible.
I just got done shooting a portrait of a man from Finland. His English was pretty good, but I still found myself making a lot of hand gestures, including the dreaded "thumb's up".
The first time I flashed the awful thumb, my subject startled a bit- as though I had flipped him the bird. I instantly realized my faux pas: many a hand signal means something else in other cultures. (Such as our "OK" symbol basically means "asshole" in certain Asian countries.) I do not know if a thumb's up is offensive in Finland or not, but it seems very possible that it could mean "up yours, shit tooth".
I never, ever use the "thumb's up". I know it's totally lame. So it's baffling that it was my instinctive first move with this guy.
But more horrifying is the fact that I continued to use it. I must've flashed my thumb half a dozen times, including as I walked him out. "Okay, thanks! See you later! Up yours, shit tooth."
I'm an asshole.