For a guy with a Ph.D. and two degrees in English, you certainly use your fair share of bad grammar. What gives?

I assure you that when I use "bad" grammar, it's no accident—at least 99.8% of the time. (The other 0.2% slips past me. But, hey, nobody's perfect!) As I used to tell my college writing students back when I spent my days in front of a classroom, it's perfectly OK to use bad grammar as long as:

  1. You know when you're doing it,
  2. You know why you're doing it, and
  3. You know how to do it well—that is, effectively.

But if you don't know those three things, then stick with the prescriptivist grammarians and adhere to the rules. Ain't nothin' wrong with that.