I have bad luck with finding polite opponents or it seems most people are just bad losers but most of the time people who are the underdogs are trying to get under my skin to throw me off balance. Its really nice to find some players who can take a hit without getting all aggro instantly.
Pokerstars is the client where i find players to be more sportive than the no-deposit sites where the fish on low limits are being d*cks because they are frustrated for not winning the jackpot without any effort/learning.