Lets say you're warming up against someone for either friendly or competitive play and they only hit slice shots with wicked under spin AND side spin (the kind where the ball almost bounces back towards the net even when hit deep). Is it rude to hit only these shots during warm up or should they make an attempt to feed normal balls to their opponent? I had dealt with this and found it slightly annoying but since all of his shots are like this even during a match, I didn't know if he even knows how to hit a flat or topspin ball. It was just friendly doubles too so I wasn't expecting a great warmup anyways. What do you think?