My son is in college and taking economics courses. We meet for dinner once a week:
Me: The service in here is awful. This is making me really mad.
Son: Why? They're saving you money. Won't you just reduce the tip until you are indifferent?
I wanted a reason to be mad, not indifferent. I was hungry and pretty cranky, so I explained, curtly, how market failure in the food service industry made it so that reducing the tip would not fully compensate me for my losses. I was then told, in so many words:
Son: That's a dumb argument.
And it was. But don't tell him I admitted that. I did reduce the tip, and even though I didn't reduce it very much, I'd feel better now if I hadn't. I'll see if Mr. Smarty Pants can explain that.