I was bullied for a couple of physical traits.
I was born in the early seventies and I'm a white girl, so round butts were socially undesirable until much later when JLo made it cool. In my family I was called BB, Bubble Butt, black girl's butt. Kids made fun of me too, all the way through grade, middle, and high school. When a guy found my butt sexy and was being genuine, not creepy, I couldn't accept it.
I also had cellulite on my butt and outer thighs since the age of 10. Wearing swimsuits was hell. Some other kids, especially a couple of really cruel boys, made fun of me when I wore a swimsuit. I was always a little plump, but they treated me like I was obese and hideous. These were in the days before video games, so there were not nearly as many overweight kids and acceptance of that when I was growing up. In grade school kids would call me fat when I was merely plump, there was only a couple of obese kids in the school and I didn't even come close.
I really hated my body until my mid-thirties, and somewhat hated myself because of my body.