Who actually uses good grammar?
I got a chuckle out of last Sunday's "For Better or For Worse."
The reality is, of course, that most of us (even English teachers) don't use "good" grammar on a regular basis and do just fine. There are many grammars out there, and what gets labeled as "good" is only one of them. The ability to use it does bring a kind of status, but also resentment--you come across as educated, but also possibly out of touch. Grammar is related to environmental context, and the most skillful speakers know which grammar to choose for a given situation. This comic does a good job of highlighting that tension, I think.