My experience is there's also a fundamentally inborn notion of "fair price" and "fair pay" that people are born with, that they have to be educated out of to operate successfully in the modern economy. It's one way in which our system is kinda anti-human—it assumes a kind of game-playing that's seen as wrong by people, naturally, and you have to play that game or you can't succeed. "What the market will bear" doesn't feel fair to people until they're made to see it as fair.
Price is just a symptom or manifestation. People naturally see it as unfair to take advantage of someone based on a power imbalance or information asymmetry. So charging an excessive price or paying a starvation wage is just one way to take advantage, but there are other non-monetary ways as well. Attempts to impose "fair" price or wage controls by legislative fiat or cultural norms are doomed to fail because they don't resolve the underlying cause.
