Sean's "secret admirer" takes each of the rings off her fingers and lays them on the side of the bathtub. When she turns on the bath water, the shot of her hand shows one of the rings still on.
The label on the whiskey bottle that Sean is swigging from throughout the party changes from a generic label in close-ups to Jack Daniels in the long shots.
When Lauren and Lara snort cocaine, traces of cocaine disappear and reappear around Lara's nose.
In the split screen sequence, when Sean meats Lauren in the corridor, she takes off his glasses, but when the screens join she's clearly standing too far away to have been able to reach them.
When Lara does a hand stand while talking to Lauren, her shirt covers her stomach even though she rolled it up before she started.
In Victor's monologue he states that he flew to London on a DC-10, a three-engined aircraft, yet in the shot on screen we can clearly see that the plane is a four-engined Boeing 747.
When Sean Bateman opens the first love letter from his secret admirer, he looks down at his lap in response to the silver star confetti before it actually empties from the envelope.
When the secret admirer cuts her wrist in the bathtub, air bubbles escape from her blood vessel before the blood. There are no air bubbles of that size in the human bloodstream - it was obviously an appliance (or other skin addition) that was not filled to capacity.
When Paul gets kicked out of the guy's room for hitting on him, he lights a cigarette with an ordinary disposable lighter, but we hear the distinctive sound of a Zippo.
Although the location for the film is a fictional northeast college called Camden, there are two palm trees that can be seen in the parking lot of the hospital scene.