I have a tendency to jump on opportunities to work a bit outside my normal comfort zone, within reason, and my art is all over the place in terms of style and subject matter anyway, so I don't usually mind being asked to draw something different than I usually do. It's a nice challenge.
HOWEVER, my biggest art pet peeve is probably people looking over my shoulder to make comments like these:
"You're such a good drawer!" (I am not furniture.)
"Will you draw me?" (No.)
"Is that you?" (Also no.)
"Why are they naked?" (I'm not done yet!)
"Will you draw something for me?" (Sure, if you pay me.)
"You're so talented, I can't even draw a stick figure!" (You could if you'd been doing this for 20+ years.)
...Also people immediately assuming that I learned everything in the like, year and some change I spent at an art school, and not via two decades of practice 