[krisoft]

From the seller’s perspective? Because they own a thing which is worth less to them than the buyer promised for it. Therefore they can profit greatly from the deal.

This is not the story of some happless kid swindled by a brown ice cream vendor. This is a sophisticated business person who has, prior to signing a legally enforceable contract to buy the brown icecream as-is, talked publicly about how the ice cream is just brown and not chocolate.

Why did the buyer made that contract to be written and then signed it? The potential buyer of the brown ice cream was not taken seriously initially. Everyone, including the seller, assumed that he is going to flake out and not go through with the transaction. The buyer has seen that he is not taken seriously, but he really really wanted to own the brown ice cream at that time. So the two parties willingly went into a written agreement that the buyer is going to pay a lot of money for the brown ice cream. Since the seller had concerns about the flakyness of the buyer, they both instructed their lawyers to write the contract as ironclad as possible. And what gives teeth to contracts like that, is that they can be enforced through the court system.