Everyone's favorite super-simple QR, COS 109: Computers In Our World, is taught by adorable professor Brian Kernighan, who had this to say about his profession:

(During a topic about cell phone surveillance)
Prof: I'm willing to bet that most of your cell phones are on. (Nods from students.) I have one but it's never on. I use it once a week or so to let my wife know I'll be late for dinner or something like that. (Pause). Yet another reason I'm not qualified to teach this class.

Thank God for Click For Credit.