Other mistake: When Happy hits the ball in the alligators mouth, he is on the complete other side of the lake where the gator is located, and there is a crowd of people blocking his view, but somehow he can still see through the people and over the lake, to notice the gator taking his ball.
Revealing mistake: In at least one scene, you can see the ruts that the filmmakers made in the greens to make Happy's putts go where they wanted them to.
Revealing mistake: In the scene where the Volkswagen is driving on the golf course to run over Happy, you can see tracks in the ground where the car had already been.
Continuity mistake: The exact same shots of the golf ball sailing through the air are used two or three times, especially during the last golf tournament.
Continuity mistake: When Happy is about to putt and the tower starts to fall, his caddy is behind him. In the next wide-angle shot, his caddy is in front of him, or at least between Happy and the hole, where before Happy was between him and the hole. A couple of shots later, when Virginia runs up to Happy, the caddy is back to his old position again.
Continuity mistake: At the final golf tournament, Happy's grandmother tells him she just wants him to be happy. In one shot, both her hands are up towards Happy, in the next shot only her left arm is up, and in the next shot both hands are up again.
Continuity mistake: When the alligator takes off with Happy's golf ball in his mouth, he takes off and slides down into the pond where he goes through a patch of water-lilies. When Happy dives in the water after the alligator there are no water-lilies.
Continuity mistake: After Happy gets hit by the car he's lying on the ground and you can see he's only wearing the Subway shirt. But when he tees off near the end he's wearing a shirt over the subway one.
Suggested correction: He's wearing the orange button-down shirt the whole time.
Continuity mistake: Happy and his new caddy are discussing the shape of the green and the caddy says the green is slanted to the left. When Happy tells him it only seems that way because he's missing a shoe, the caddy is standing with his feet shoulder-width apart. When the camera cuts to the close-up of his feet, they're together, yet the caddy didn't move.
Continuity mistake: When Happy wins at the end, people start running towards him. One of these people is a girl with a blue shirt. Then there's a shot of cheering people that are standing to the side without running to Happy, including Richard Kiel, and the girl with the blue shirt.
Other mistake: When Happy is trying to "fix" the air conditioner in his grandma's room you can clearly see there is a white board in back of the machine. When the machine falls out and hits the lady on the ground you can see it's no longer there.
Continuity mistake: When Happy and Bob Barker are fighting they roll down the hill, just as it appears that Happy wins the fight Bob grabs him by the throat. Bobs pants have a small wet stain on the butt area. After he hits Happy and walks away the wet spot is the whole area of his butt.
Continuity mistake: At the Waterbury open, when Happy first putts, there a a guy telling his friend, 'this is pathetic' There is a cluster of trees right behind him. Then when Happy punches him, the trees are no where near him, but way in the distance.
Continuity mistake: Near the end of the movie during the final round of golf Happy is wearing a tee-shirt under a button shirt that is open. All through the round the tee-shirt goes from a Subway shirt to a white shirt with a brown strip across the chest. It is much more noticeable during the last putt. He has the stripe shirt while putting then when he makes it and every one rushes to him it is the Subway tee-shirt.
Continuity mistake: At the beginning when he enters the apartment he barges through the door leaving it open but when the lady walks in she has to open the door.
Revealing mistake: When Happy tees off at the AT&T Invitational, he swings his club about a foot above the ball, yet apparently he hits it successfully.
Deliberate mistake: In the beginning of the movie when Happy first discovers his swing, the balls that hit the people down the street are never visible upon impact.
Continuity mistake: When Virgina hits the puck during the skating scene, the puck can be seen going in that blue area in front of the net. In the next shot, however, the puck is only halfway towards the net.
Plot hole: The bet between Happy and Shooter is in no way legally enforceable. Even if it was legal to make such a bet and it have it be enforced, the only person who can verify it was ever even made is Virginia who's obviously biased as Happy's girlfriend. The only way Shooter would actually honor the bet is to keep his word, which is completely out of character (he is the bad guy after all). And I'm sure with the money he's earned he can hire a bodyguard to protect him from Mr. Larson.
Revealing mistake: When Happy jumps on the alligator in the pond, it is very noticeably a rubber (fake) alligator.
