Bad Teacher will have you laughing like it is an occasionally funny movie

-- Local show times, theaters, trailer.

Remember when the runaway success of Bad Santa resulted in a string of copycat classics?

But then, who could forget Bad Nurses, the misanthropic adventures of three nurses who shot up their own morphine and used ice cube trays for bedpans?

Or Bad Tax Attorney, who couldn't tell a 1099-B from a 1099-R? And it would take more space than I have available to cover the greatness of later works such as Bad Rabbi, Bad Racist and Bad Walrus.

Despite setting themselves up for an inevitable comparison to a great comedy, these films succeeded because their raw, throbbing humor was too potent to deny. The same can't be said for the latest entry to the well-trod Bad subgenre Bad Teacher.

After her fiance dumps her for being a shameless golddigger, Cameron Diaz is forced to go on teaching middle school. There, she swears, ignores her students and shamelessly manipulates everyone around her.

Affable gym teacher Jason Segel makes a pass at Diaz, but she brushes him off to pursue wealthy new substitute Justin Timberlake. But she's got a rival for him -- chirpy super-teacher Lucy Punch, who wants Diaz and her bad attitude kicked out of school.

With its crude humor, casual drug and alcohol use, and overall dissipation of a main character who doesn't give a damn, it's hard not to compare Bad Teacher to Bad Santa. This is unfortunate in the same way it's unfortunate to compare a turkey sandwich with wilted lettuce to lobsters stuffed with tacos. It isn't that the sandwich is bad (though it would have been much better if that idiot boyfriend could remember to shut the fridge all the way -- seriously, it is not that hard). It's that, well... you just know you could be eating something better.

Even though in one sense that's all you really need to know, I don't like harping on comparisons like that for the same reason I don't like comparing my younger son to his older brother the heart surgeon: because then he starts crying until I remind him that crying is for losers who'll never be as good as their big brothers.

So what about Bad Teacher on its own merits? Decent. Decentish. Yeah, pretty decent. More specifically, it's a somewhat frustrating mix of really funny moments and a lot more should-have-been-funnier ones. There's something missing to the writing -- most times, it just throws Diaz's crassness and rudeness out there like that's enough of a joke on its own and now it is time for celebratory nachos.

You need wit with your dry-humping, damn it. Wait, actually, that scene was pretty funny. Director Jake Kasdan was a great choice for Bad Teacher -- he's done great with comedies Walk Hard, The Zero Effect and The TV Set -- and he does a, what's the word, a decent job juggling Bad Teacher's subplots about breast implants and test-stealing and kids' romantic problems, all while striking comic gold just often enough to keep it functional as a comedy.

(Comic gold, by the way, is identifiable from the common kind by the fact that when a brick of it falls on your head and squirts your brains out your ears, bystanders laugh rather than scream.)

Meanwhile, Diaz is fairly funny, Segel is more fairly funny, and Office regular Phyllis Smith is so hilarious we're surely just weeks away from seeing a spate of comedies starring fat middle-aged women.

As a whole, though, Bad Teacher is that vaguely disappointing type of comedy where you always feel like you should be laughing harder than you are.

Grade: C+

* Contact Ed Robertson at edwrobertson@gmail.com. His fiction is available on Kindle, Nook, and through Smashwords.