The way I see things is thus:
"I dominate in my Arena, why can't I win here?"
"Because you aren't in your arena anymore"
We get used to fighting the same old folks we develop an understanding of patterns. Bringing new blood in upsets the patterns and many folks don't compensate. Some rage and argue that "GA stinks!" because they have difficulties. Others rage and argue "GA stinks!" because they dominate too easily and want a challenge. Still others don't rage and play the game, hoping for a win but accepting of a loss.