Continuity: In the scene on the roof after the power transfer, Hannah falls through the sky light and Matt yells down to her. You can tell the close-ups on Matt were re-shot because Matt's hair is longer and styled differently in between shots.

Continuity: When Matt and Jenny are on their first date the way she is holding her wine glass changed from shot to shot. First she is holding the bowl of the glass, then the stem, then back to the bowl.

Audio problem: When Jenny makes the cab stop, Matt says something, but his lips never move.

Continuity: When Matt is chasing the street robber at the start of the movie, the robber is out of sight of Matt when he drops G-Girls purse under the silver car, yet Matt hasn't seen this and cannot see the purse yet knows where to pick it up.

Continuity: At the end of the movie when Hannah and Matt are at the fashion show, Hannah's hair is curly but in the next shot of them leaving her hair is straight.

Continuity: When Jenny makes the cab stop, the driver gets out and he is a middle-aged man, with black hair and no glasses. The next shot shows them with an older man wearing glasses (and it looks like he has a moustache/beard).

Factual error: When, on their second date, Jenny sucks in air and pulls a cab backwards, the driver spins the tires trying to go forward. The smoke rolling off the tires does not get drawn backwards towards the suction.

Continuity: While Jenny is cutting vegetables (just before Matt breaks up with her), you can see bits of celery all over the knife. When she starts to bend the knife all the bits left on the knife have disappeared.

Continuity: During the last few scenes in the movie, when Heather asks Jenny if she needs help with the plane, they knock knuckles together. When the shot is taken from behind Heather, she is shown wearing gloves, but when the shot position changes to behind Jenny, the gloves magically disappear.

Factual error: In the opening NYC MTA subway scene a couple minutes into the movie, the characters are riding an R subway train. The letter is visible behind Luke Wilson's head when he asks, "Wouldn't it seem a little - yeah". When Luke Wilson runs off the train after a robber a minute or two later, they run up a staircase that says "uptown N R W trains". When they run out of the station, however, they are running out of the Franklin Street 1 stop. The red 1 line and the yellow N R W line do not intersect anywhere near Franklin Street, so it would be impossible for them to have exited an R train at the Franklin Street station.