Those who can do, the saying goes, and those who can’t teach.
How about a filmic footnote: Those who teach often end up onscreen.
The latest example is “Bad Teacher,’’ starring Cameron Diaz in the title role. It opens Friday. Diaz joins a long line of actors who’ve put chalk to blackboard in front of a camera.
Hollywood has always favored certain jobs: cowboy, gangster, soldier, superhero. Teacher may not rank as high, but it’s definitely up there. And what the profession may lack in popularity onscreen it more than makes up in prestige. Teaching roles attract Oscar nominations the way red carpets attract revealing dresses.