From Ubik [1], by Philip K. Dick: The door refused to open. It said, "Five cents, please." He searched his pockets. No more coins; nothing. "I'll pay you tomo

From Ubik [1], by Philip K. Dick: The door refused to open. It said, "Five cents, please." He searched his pockets. No more coins; nothing. "I'll pay you tomorrow," he told the door. Again it remained locked tight. "What I pay you," he informed it, "is in the nature of a gratuity; I don't have to pay you." "I think otherwise," the door said. "Look in the purchase contract you signed when you bought this conapt." ...he found the contract. Sure enough; payment to his door for opening and shutting constituted a mandatory fee. Not a tip. "You discover I'm right," the door said. It sounded smug. [1] https://en.wikipedia.org/wiki/Ubik https://en.wikipedia.org/wiki/Ubik