A lot of Adam Sandler fans have a thing for the song Louie sings to Catherine near the end of the movie.
Steve Martin only had one funny scene: the scene where he dances with Liev Schreiber. Even more funny when Mrs. Munchnik (Madeline Kahn) catches them in the act; when she says "Philip?" she really looks like she finds it funny before going back into character.
The scene where Madeline Kahn has something of a conversation with Liev Schreiber, who is on the other side of the door and whom she thinks is the serial killer.
Also the way she handles an obscene phone call,
One particularly funny section of dialogue is when the vet rants about how women put too many pillows on their beds.