it bounces.
Learning how to create/negate spin on a tennis ball is just one of the things that makes tennis such a challenging sport, but it's also one of the things that makes it so fun. The first challenge is learning to read spin (even while you're racing to return a cross-court volley!), but watching what your opponent does with his/her racket can tell you a lot! If tennis balls weren't fuzzy, it would be really hard to for the spin on any particular hit to create a significant difference to the way that the ball behaves, but thanks to the physics of how the felt that covers regulation balls, learning to control spin can become an important strategy in winning points, sets, and matches!