Continuity mistake: In the scene in the restaurant where Tom Cruise and Dustin Hoffman are trying to order breakfast, Hoffman's character fixes the salt and pepper shaker a certain way. In the next shot they are opposite the way he fixed them. Then in the next shot they are back to the way he had fixed them.
Trivia: Dustin Hoffman and Tom Cruise spent a lot of time with a man and his autistic brother, whom the man took care of much like the way Charlie has to take care of Raymond. A lot of the things Cruise and Hoffman did in the movie were things they witnessed the two brothers doing. One example of this was when Raymond and Charlie lean their heads against each other's at the end. Had Cruise and Hoffman not seen the brothers do that, it never would have been in the movie.