I'm a 3.5, but I've played at USTA levels ranging from 2.5 ladies up to 8.0 mixed. I can't say I've seen it all, but I've seen a lot. Many times on this board, someone has suggested that lower-level players are more likely to make a bad call in their favor (that is, hook) than higher-rated players. Now that I'm playing with more 4.0s and even some 4.5s, I'm starting to think there may be some truth in it. This is not to say that lower-level players are dishonest or cheat more or any of that. I think there might be more bad line calling in lower-level matches for a bunch of reasons. The biggest culprits, I think, are spin and speed. When I play players who are rated lower than me, I hit a ball that they are perhaps not used to (that's what they say afterward, anyway). It comes a bit faster (and in doubles it might be coming off of my racket at net, which makes it seem faster). And it's likely to have slice or topspin, which makes the ball behave in ways the opponent does not expect. Surprise, more than anything, seems to cause a bunch of bogus "out" calls. I mean, if your experience has always been that a ball X feet over the net will fly long, maybe it gets easy to assume that result will hold even if the ball has spin. Or maybe the superior ball-watching skills of higher-level players help them see the lines better or judge the likely flight of a spinny ball better? I don't know. What's weird is that I have the opposite problem when I play at higher levels: I am constantly surprised that people are calling balls in without much hesitation. I will hit a topspin lob or good slice serve -- the kind of shot that drops at the last moment -- and I will brace myself for the hook that never comes. All I get is "Good shot." What do you think?