One of the reasons is Sean William Scott. We all know he can play a smart ass and jackass. But what most people don't know is that he's actually very talented. He veers off a little here in that he plays a loveable goofball with a slightly violent streak (like Happy Gilmore). But he's even more "aw shucks" and it really works. Some of the lines he delivers because the character is so dim are absolute comic gold. The rest of the cast does a decent job of providing the needed caricatures that a sports comedy needs. They all have them and this one is on par with the best. In fact, all of the dialogue is very cleverly written and well timed.
The only beef I have with the film is some of the inconsistencies and continuity. It's a Canadian made film and they really play up the stereotypical Canadian accent. As a Canadian, it rubs me a bit the wrong way when they really play it up. We don't all sound like confused Americans with head trauma. In fact, most of us don't. Yes, our "out" does have a lot less of a drawl than the Americans but it isn't that different. When they had a character with a Canadian accent, the only one that was believable was Liev Schreiber. It was just enough and he made it very convincing. The rest were over the top and obvious attempts to make Americans think it was quaint and get them to watch the movie. The other continuity issues are only recognizable if you know a little about Canada and hockey. The MTS Centre is in Winnipeg but it was home to the Quebec team here. There's lots of local Brandon, MB advertising on Halifax's boards, etc. But that's OK. There probably just wasn't enough budget to fully modify the sets for realism. And even the big budget films don't get it all right.
See it. The laughs are definitely worth the time.