Squats

When you do a squat you're supposed to go all the way down, then all the way back up. It's cool if you're squatting alone and you can't tell, I used to do that, but today I was on the rack right next to one of the personal trainers who was teaching a guy to squat. He loaded the guy up before the guy learned how to do the move so the squatter couldn't even go down past 45 degrees.

Personal training is kind of expensive, the guy should be be able to teach you how to squat. Even this kid knows how to do it. Perfect form.