Sumdood walks in, aggressively tells us that he needs coolant for his car. We politely look it up for him, and show him which jug is what came with his car. We have no idea what they put in at the el-cheapo lot where he bought it. He exits.
He is back within the hour, wondering why his car isn't any cooler.
And when it is explained that what he really needed was refrigerant, he buys one can of the cheapest stuff. He brother's friend can put it in.
Comes back later with a hole punched in the bottom of the can. Is angry that we won't return his money.
This is why we drink.