as a rule yes absolutely considering i mostly play heads up games. if I don't why the hell am i playing occasionally regs sit me and I have to fight it out. However I still think I have an edge there just would prefer to avoid regs entirely.
the thing I have always found myself reminded of though is your opponents will always surprise you. from watching a player i know to be bad do a very impressive sophisticated
bluff, which actually was very good play, to a reg i know to be good doing something shockingly bad.
the trick is to be alert i sussed the bluff but i was surprised at it none the less.
the thing is though the reason your the best in your game if you are is because your not playing a big enough stakes game and the reason for that is probably because your not good enough to. of course build a bank roll and move up etc maybe your just on your way.
my point is though arrogance wont often turn a decent winner in his game into a loser instead it will stop him recognizing his leaks and how he can improve. it wont make him lose in that game often but it may well be what stops him winning in a tougher game another time.