A convenience fee is a charge added at checkout for the privilege of paying. The convenience in question is usually the seller’s: they would rather you pay online, and they would rather you pay for the system that lets you. The word has been attached to the fee so that the fee appears to be a favor.

The test is to ask whose convenience. If you could decline the convenience and pay the listed price, the word would be honest. You cannot. The fee is mandatory, which is to say it is part of the price, which is to say the listed price was a fiction. The euphemism exists to keep that fiction on the page for one more screen.

The family includes “service fee,” “processing fee,” “facility fee,” and the ticketing industry’s masterpiece, the “order processing fee,” which charges you for the act of being charged. Mamet’s “Improved!” on the box is the same move: a word that sounds like a benefit, stuck on a thing that is not one.