Bitching & Moaning
I have yet to experience a single tournament where at least one top player didn't complain about something. Molehills become mountains as the slightest little thing sets someone off. It could be just a natural response to gameday pressure mixed in with a bit of healthy ego. When it happens some just can't recover while it clearly fires up others. I've seen many top players turn anger inward and use it as a positive force to produce some truly spectacular performances.