Bad Teacher looks like it will be a typical redemption comedy. You know, somebody is on the wrong path, they hit rock bottom then get redeemed, usually with some public display of contrition and a happily ever after moment at the end. It's a genre; it's a formula. Bad Teacher has none of it.
Cameron Diaz is amazing as a slacker with a teacher's license looking for a sugar daddy. She's shallow, insensitive, lazy and manipulative. And those are her good points. What I liked is that - I'll do this without a spoiler - she doesn't change over the course of the movie. It's more like she runs out of energy looking for what she desires and finds that what she has isn't so bad. Watching her go through the motions, being a jerk and making bad decisions is hilarious. But what I just described is only what makes Bad Teacher a good movie. What makes it a great movie is...
Lucy Punch. Lucy is an amazing comic sidekick. You've seen her before as the wicked stepsister in Ella Enchanted, the hapless lifestyle reporter on the short-lived TV show The Class or any of dozens of bit parts in TV and movies. Not really destined to be a lead actor, she dived into the part of the neurotically competitive straight-arrow teacher across the hall with gusto, not afraid to make with the crazy. And make with the crazy she does, giving us sight gags and punch lines in every scene. I am in awe.
Bad Teacher could easily get lost amidst all the other movies released in the summer season because it doesn't look like anything special, but if you're looking for some subversive laughs and nothing sweet or redemptive, seek out Bad Teacher.