People at the gym who run on the treadmill at an impressive 10+mph, but are hunched over and supporting half their weight on the handrails and basically floating over the treadmill. Guys, please stop, you aren't impressing anyone.
People at the gym who move an impressive amount of weight (say 250+ pounds on the bench) but go through a range of motion of about 3 inches. Guys, please stop, you aren't impressing anyone. Especially you, old guy from Benny Hill, who knocks out 100 reps of everything with a not-so-impressive amount of weight and a 1 inch range of motion.
Highly perfumed women at the gym, hate it, totally knocks me out of my "angry mode". Can't bring myself to tell them to stop though.