Trash talk during pro sports is inevitable. With all that testosterone on the field/court/rink/etc, it's just going to happen. Athletes at pro levels have spent their entire lives finely tuning their bodies and perfecting their crafts. They're confident and cocky.
Luckily with modern technology, microphones are EVERYWHERE on the field of play, giving the sports fan an added layer of inclusion in the game. Those mics picked up Kevin Garnett's trash talk the other night. He sure is a potty mouth!