Continuity mistake: At the end of the film, when the camera is focused on all of Mary's suitors in her apartment, you clearly hear Matt Dillon say "Dom?!" off camera (as if he entered the room and was surprised to see Woogie there). A few seconds later, he bursts through the door, sees Woogie and says "Dom?!". (01:45:10)
Continuity mistake: Ted makes fingernail marks in the floor when Puffy is pulling him along. Two things wrong: His fingernails aren't even touching the floor when he makes them, and the marks seem to disappear in almost all of the long shots. (01:32:30)
Continuity mistake: When Ted enters Healy's apartment and hides behind the door, there is a nearly full bottle of vodka on the table. It is full of caramel-colored liquid. A minute later, when Ted brandishes the bottle to threaten Healy, the bottle is empty.
Continuity mistake: Near the beginning of the film when the time period is 1985, Ted is with his friends and the camera shows Mary biking into school. After the fight Ted offers to walk Mary and Warren home but Mary doesn't have her bike with her.
Continuity mistake: When Mary and her friends are eating lunch, Pat is sitting behind Joanie. There is enough room for someone to walk through. At the end of that scene, when Mary says that she has a vibrator the distance between Pat and Joanie has increased by double if not tripled.
Continuity mistake: As Ben drives up to Mary's house to take her to the prom, you see the front of the house and the front door with the door knob on the left side of the door. When the door opens though the handle would have had to be on the right. No way the door could open the way shown in the movie if the handle was on the left.
Continuity mistake: When Ted is fighting with the dog, the carpet under the table changes back and forth between flat and bunched up.
Continuity mistake: While Healy and Tucker throw speed at the house, the cucumber slices on the couch move around between shots.
Continuity mistake: When we're introduced to Mary's neighbor sunbathing, the Kool packet next to her changes positions between shots.
Continuity mistake: When Ted confronts Tucker and Healy at Healy's apartment, three piles of dog feces are visible on the floor (next to the door,) when he enters. Several minutes later, when Ted leaves, only one pile is visible.
Answer: Because he is ignorant and doesn't know anything about disabled people, he actually doesn't realise what he is saying is offensive.