I see bad warm up etiquette all the time that it drives me crazy. Most common is guys that chip the ball back and it barely makes it past the service line. I even see drop shots being attempted during warm-up. Also very aggravating is when guys want to return my serve warm-ups and they hit them all over the place. If you can't get the serve back to me then just catch it and hit it back please! I also see guys hitting winners during warm-up...sharp angles, etc. Really mind-boggling stuff sometimes.
Currently using a Graphene Speed MP w/ multi/copoly hybrid @ 55/52