Don't Be a Party Pooper
Why do "players" wait until the last minute to run to the bathroom before a match, and do whatever business they have to do? They've usually been sitting on the deck or in the players's lounge, watching a football game, at a tennis club, for an hour prior--and, it suddenly dawns on them, just as court time comes up, that they gotta' go, gotta' go, right now! They'll do it every time!
"...the human emotional system was not designed to endure the mental rigors of a tennis match." Dr. Allen Fox