Stupid customers

I simply cannot stand customers who tend to explode at you when what has happened is not your fault. I recently had a customer who can only be described as a genuine, first edition asshole. He wanted a replacement lightbulb, we didn't have it, but we sold the lamp. He explodes at me while his little M&M munching little monster is screaming "Daddy! Daddy!". I have no control over the stock, and I wish people would realize this