As long as the person isn't an *** about matters, a know it all and stubborn about what he (doesn't) know, I do not mind talking and correcting.
My Fav. thing to do is when there just blabbin away is;
"Um, excuse me, but, um, did you go to high school around here? Graduate from around here? Yea? What school?"
There answer here _____________.
"Oh, thanks, it's just that, well, I'm looking to purchase a house around here and the schooling is paramount in my kids life and I need to find a better school than the one you went to. Not so nice you can not read the big bold letters on the side of the car saying DODGE!" Thanks for your time, my condolences to your lack of education and poor eye sight, please move along, were done here tonight. Thank you, bye bye now, see ya etc.........."
And yes, I have done this dozens of times.