Kevin Costner plays Roy McAvoy, and ex-golf pro who runs a driving range in the middle of nowhere (520 miles from anything, to be exact). The film opens with a horrible song, which is followed by a goofy country soundtrack that was, unfortunately, written for the movie. Why is it that music that was written specifically for a movie is never any good? There are exceptions, of course, but none of them can be found in Tin Cup. However, despite the sub-par soundtrack (no pun intended), this is a surprisingly satisfying film.
(spoilers) It's not about the game in Tin Cup, which is good, because that would have ruined the movie. There is a delightfully rich relationship between Roy and Molly Griswold (Renee Russo), who is in an unhappy relationship and becomes the love interest for Roy in the film. Molly has problems of her own that parallel Roy's own struggle with his life as well as his golf swing. She is a psychologist, but she gets hurt a lot. She can always tell when people are lying to themselves, but can't seem to tell when people are lying to her. Roy spends the majority of the film trying to get her to leave an unworthy boyfriend who, of course, turns out to be a total dick, and continually makes awkward advances of his own. Many of his amorous advances resemble something confused and totally wrong that you might expect from someone like Travis Bickle from Taxi Driver. Roy just doesn't understand women, and Molly doesn't seem to know what she wants in a man.
Cheech Marin rounds out the cast in a fairly serious role that strongly contradicts his traditional roles, and he pulls it off surprisingly well. He is Roy's close friend and ultimately his caddy in the U.S. Open, in which Roy plays as sort of the thinking man's Happy Gilmore. It seems that his infatuation with Molly has caused him to lose much of his skill (`the shanks,' I believe it was called), and he tries just about everything to get his swing back. He uses all of those ridiculous infomercial devices that he made fun of Molly for using earlier in the film, and even attempts some witch doctor-like stuff, like getting drunk and playing hung over. Oops.
There is very heavy emphasis on the meaning of the golf in the movie, rather than the golf itself. It is made clear in many different scenes that winning or losing or even playing golf are not the things that should be focused on when watching this movie. It is the way that golf is used as a metaphor for life that is important. There is a part in the movie where Roy breaks a golf record, but he still gets no respect afterward, because he had yet to change as a person. Merely beating a record because you took less shots is meaningless what's important is what you learn or how you change as a result. Even more importantly, near then end of the film, Roy takes shot after shot at the final hole, dropping all after ball into the lake, but he keeps taking the shot, rather than attempting to make it to the green safely with more than one shot. When he keeps telling Cheech to give him another ball, it becomes very clear that winning the tournament has become secondary to him. He has set a goal for himself, and even though he knows that it will cost him the tournament, he still seeks that goal.
Notice how when he finally does make that shot, he is way above par, but he still gets a huge response from the crowd. Tin Cup has a sort of Rocky-style ending, in which Roy loses the tournament, but he still wins his conflict with himself. Besides that, the movie doesn't leave us with the feeling that we are seeing a temporary high point that will likely be followed someday with the same troubles that were overcome in the film, which is something that even great movies like As Good As It Gets are guilty of. Roy has not made the most tremendous achievement possible, because he did lose the tournament, but he has also managed to qualify for the U.S. Open tournament for the following year. He lost the golf game, but he has made a significant accomplishment in his life that is especially clear when you compare his character from the beginning of the film to that at the end of the film. Character development is one of the most important things about meaningful film, and it is one of the strong points in Tin Cup. Don't watch it for the golf, watch it for the well-written script, the great acting, and most importantly, for the valuable lesson that can be learned from it as a perspective on life.