"This car is disgusting. You should clean it up."
Pro tip: If you're looking for a clean ride, go take that bus that runs on natural gas.
If you're making this comment as one of our friends, then maybe we should reconsider your friendship. Do you not know me? Do you think I don't know that my car is dirty? You come in here all high and mighty, as I'm offering to drive you to Taco Bell for your cheesy gordita crunch fix, and you have the gall to insult my ride? Ridiculous.