Since the movie was filmed in Canada, many of the minor characters (as well as lead actor Ryan Reynolds) are played by Canadians. Three of the supporting actors - "Fred Ewanuick", "Mike O'Brien" and "Cavan Cunningham" were regulars on the Canadian sitcom "Corner Gas".
In the opening scene when Chris is leaving the party on his bike, he paraphrases a line from Bruce Springsteen's "Thunder Road": "It's a town full of losers, and I'm pulling out of here to win."
When Chris, Jamie and his Mom are watching home videos in the living room, in one of the video shots, where there is a close up on Chris' "fat face", you can see part of his fat suit peeling off his chin.
At the start of the movie when Jamie and Chris are at her graduation party and they are in her room, when Jamie first jumps on the bed she is rolling around and you can see her underwear. About a minute later she is tickling Chris and leans down towards his abdomen, and her butt is in the air towards the camera, you can clearly see she has on black shorts underneath her dress. Then another minute later she leans over again and there are no shorts!