Hey man Im not going to sit here and tell you how to be. BUT, if it were me, (ill start this by saying im a white guy so I cant say for sure how that situation made you feel) BUT, I would tell that guy at Autozone how you feel. Ask him WHY he thinks you would be in an Impala or Nova. Ask WHY he thinks he knows more about you than you do.
People need to be called out on this stuff. Too many times I hear stories like that and I cringe every single time. I literally dont have the sack to say something like that to someone I know absolutely nothing about. Just irritates the crap out of me....