Continuity mistake: When Buddy stays over night at Dave's place the first time Dave ends up sleeping on the floor with his teddy in his arm. When Buddy wakes him up and takes a picture the right arm of the teddy points into different directions from shot to shot. (00:29:30)
Factual error: Adam Sandler's apartment is near the Brooklyn Bridge. His office is in downtown Manhattan since you can see Brooklyn Heights and the Brooklyn Queens Expressway from his boss's office. Jack Nicholson pulls the emergency brakes on the Queensboro bridge when they are heading to Sandler's office. You wouldn't take the Queensboro bridge to go from Brooklyn to downtown Manhattan. (00:32:20 - 00:35:00)
Continuity mistake: When Buddy and Dave drive to work Buddy pulls the brake on the bridge. Through the rear window you see cars skidding and jamming up right behind them. Then comes an areal shot where there are just two cars braking at a distance, but when it cuts back to the view from the front the jam is back. (00:32:25)
Continuity mistake: In the scene when Dave and Buddy sing "I am pretty" on the bridge Buddy's seat belt shifts between his shoulder and his arm several times, sometimes so far down that it's not in the picture any more. (00:32:55)
Continuity mistake: When Dave and Buddy sing "I am pretty" on the bridge the window is visibly closed, only during their arguments with the drivers who go by (especially the taxi guy) the window is open. (00:33:05)
Continuity mistake: When Buddy comes to Dave's cubicle Meatball the cat sits there absolutely quietly but the beret on his head moves back and forth in alternating shots. (00:37:40)
Factual error: When Dave and Buddy get to Boston, Dave is using his cell phone, mentioning that they didn't have to take a five-hour trip to Boston just to find out that Buddy's mom was getting a Jelly Bean removed from her nose. Problem is, he's calling from the ramp staircase of Alfred Lerner Hall at Columbia University, which is in New York City, not Boston. (00:50:20)
Continuity mistake: When Dave throws the bully-turned-monk Arnie Shankman down, Arnie's head lands on the gravel and his robe under his body. Before Arnie gets up there's a close-up of his head with his robe partly under his head. (01:05:45)
Continuity mistake: When Buddy and Dave start running away in the monastery the monks are right behind them, running at the same speed. When they reach the car a few seconds later the monks are at least 100 meters away. (01:07:05)
Audio problem: When Buddy drives off from the monastery we see the wheels digging into the gravel, but the sound is that of burning rubber on asphalt. (01:07:10)
Visible crew/equipment: In the scene after the huge fight with the Buddists, Jack Nicholson speeds off in his Land Rover and cuts into traffic to get away from the monastary. If you look three cars back there is a state trooper weaving through both lanes to make sure the set is closed. He stays visible throughout the scene. (01:07:35)
Continuity mistake: When Jack speeds out into the road in the Land Rover, there are several cars in the background. However, in the next immediate shot, when we look out the back window, there are completely different cars behind them. (01:07:35)
Continuity mistake: After their encounter with the monks, Buddy and Dave speed off and come out onto a road. The first shot sees the whole car come onto the road, where there is a double unbroken line in the middle of it. The shot changes to Buddy and Dave in the car. Watch through the back windshield. The double unbroken line has turned into a single, broken line. (01:07:35)
Continuity mistake: After the fury fighters' meeting with John McEnroe Dave asks Buddy to talk to him in private. The go into the multi-purpose hall of the community center which has a stage on one side. In all wide shots and one close-up we see them talking in front of the stage, in all other close-ups in front of an inscription on the wall which is about 20 meters away. (01:10:05)
Other mistake: In the scene after Dave throws a calculator at a colleague there is a very weird 3-second establishing shot of his apartment building. In this short span shadows fall over the building twice, and it changes between fully lit and fully in the dark twice. In the end there is the silhouette of some equipment covering the lower third of the screen. (01:11:30)
Continuity mistake: As Adam Sandler goes down the courthouse steps after his third trip to court, the same red headed woman passes him twice. (01:20:50)
Factual error: Near the end of the movie Dave is trying to get to the Yankee game before Buddy proposes to Linda. One of the shots before the game is of the grounds crew doing the YMCA. The grounds crew does the YMCA in the 7th inning. (01:23:45)
Continuity mistake: When Dave drives up the parking garage of the Yankee stadium we see him coming up the ramp to the upper level. Then the camera cuts to the side and he is seen passing by a row of parked cars which weren't there before, then it cuts back to his car still on the same ramp. (01:23:55)
Continuity mistake: When Robert Merrill walks up to the microphone in the Yankee stadium it's fixed on a black stand. When Dave spots it we see a close-up where it's fixed on a silver stand. Later, when he snatches it away from Merrill it's on a black stand again. (01:24:45 - 01:25:45)
Factual error: When Dave is at the Yankee game and he is telling Linda he wants to marry her from the field, it is impossible for his voice to ring throughout the whole stadium without a microphone (even though it echoes as if he were using one.). Similarly, he wouldn't have been able to hear Linda when she shouts "I'm over here." (01:26:30 - 01:27:45)
Chosen answer: Yes, there is a deleted scene where Adam, and Jack visit her in the hospital. I'd also like to say that on the DVD, there is a section with all the deleted scenes from the movie, including the bizarre visit to his whacko mom.