I actually like playing against people who are way better than me. Like people who would win 99 out of 100 games. If they'll play me, I'll always go back for more. I'll keep replays and stuff and see exactly why I'm not winning. I have terrible execution and even worse reactions so I have to lab monster it up and play smarter to win, and that's fine.
What I have an issue with is when people realize they win 99% of the time and then change the way they play. I've seen people play really solid the first few games, then start doing dumb shit that's obviously not what they'd do in a real match. Obviously I mainly have problems with people who do it to troll, but I don't like it when the other guy is "being nice" and essentially giving mercy rounds either. If one person is playing seriously, both should be. Taunting is more respectful than not giving someone a real match.
EDIT: Oh, but I'm fine with actually not giving people a match. Time is limited and if someone wants to only play people at a similar skill level, that's cool.
EDIT: Also fine with spamming the same gimmick or mixup if the other guy doesn't know how to deal with it.