First time I was in a powerlifting bench shirt. Had about 500lbs on. The shirt tore along with my pec. Partial, muscular tear. No surgery.
Second one was about 2 years later. I was doing wide grip incline presses on the smith machine to the neck. Felt really strong that day. Had 120kg (265lbs). I had planned to do about 12 reps but it tore on rep 4 or 5.
Now I know that flaring the elbows on flat or incline is dangerous. I knew it then too but figure that since it was a 12 rep set I would be fine.
Every time i've torn a muscle it was doing a relatively easy set.
I've never had a full tear, but ruptured fibers in my biceps, triceps, lats, teres and hamstrings many times.
Hamstring tears are extremely painful. Had a softball sized bruise and swelling for 6 weeks after some glute/ham raises.