The video shows perfectly why unwritten/verbal/implied contracts are to be avoided at all cost.

Against my better judgement I recently completed some work without a written contract. It was exactly like the restaurant scene: they'd received the services and used them but started questioning the bill (after it became overdue).

I still find it strange that people view other people as a commodity like oil or pork bellies yet they expect ridiculous returns, akin to a barrel of oil spontaneously duplicating and selling itself for $300