I flip the bird for a picture if I don't want my picture taken.

Pissed off an acquaintance in high school because she wanted to take my picture, I didn't want my picture taken, she did it anyway, and I got my middle finger up just as she pressed the button.

She was pissed because:

1. This was in the days before digital photography so there was no option to delete the picture.

2. She was taking pictures for a photography class, the grade included developing the roll, and she would have gotten in trouble if that was included, so she had to start over (or so she said).