The other night, I watched "Bad Teacher." To answer your first question--"Why?"--I can only claim utter boredom and the fact that it, like Mt. Everest, was "there." Unsurprisingly, it wasn't a particularly good movie. It wasn't especially awful, either. Overall, it was essentially just a movie that exists and that will fade into deserved cinematic obscurity before too much more time has passed.
The movie stars Cameron Diaz as Elizabeth Halsey, the eponymous "bad teacher."
(DIGRESSION: Do you suppose Cameron Diaz and Salma Hayek were in the same neo-natal unit and their nametags accidentally got switched? EOD)
Elizabeth is a foul-mouthed, drug-abusing, alcoholic, gold-digger who for some never-explained reason was hired as a teacher, but who plans to leave the profession as soon as she marries her rich fiance. Said fiance, however, splits up with Elizabeth at the beginning of the movie, necessitating a return to the profession she hates--at least until she can find another suitably wealthy paramour. Enter Justin Timberlake as Scott Delacorte, a dreamy substitute teacher who happens to be the scion of a wealthy family. Elizabeth sets her sights on Scott, but he finds himself drawn to Ms. Squirrel (Lucy Punch), a treacly by-the-book teacher who quickly establishes herself as Elizabeth's nemesis.
So far, what I've described sounds like a fairly typical slapstick romantic comedy, if elevated (if that's the word) to an R-rating for its liberal profanity and drug use. What saves the movie from absolute mediocrity, however, is a surprisingly charming performance by Jason Segel.
Segel plays Russell Gettis, a gym teacher who has set his sights on Elizabeth. What makes his performance so, frankly, extraordinary, is that, in a film filled with two-dimensional characters who are largely unlikable even in their two-dimensionality, Segel somehow manages to make Gettis seem like a real, likable fellow. At times, I found myself thinking that his character had wandered in from another film--or maybe from the audience--as he observes the inane goings-on around him with an attitude of amused tolerance. Segel is not especially gorgeous, but pretty much from the moment he enters the frame, you know that he will ultimately win Elizabeth's heart, if only because he is the only "actual" person she encounters. Indeed, the only thing that redeems Elizabeth is the fact that she is ultimately attracted to--and attractive to--Russell: If he likes her, she must have SOMETHING going for her, right?
I'm not sure how good an actor Segel is--I don't think I've seen him in anything else. But whatever his level of talent, he is to be commended for elevating a less-than-appealing movie into something more than it has any right to be.