It pisses me off, i don't even wear shorts. I train calves but although muscular there's no mass, pathetic and i train them! For some reason my parents didn't hand me down calves when neither of them were lacking. I was 6 weeks premature, can this affect development..?
Then as you say i see out of shape people, some obese, some skinny, some with no muscle whatsoever but great calves, it really sucks.
So heavily genetic- I see people in the summer who look like they've never touched a weight and yet have diamond shaped calves. I had a girlfriend some years back who had some if the most perfect calves I've ever seen and she never did anything for them. Maybe it's the high heels, lol.