If it's bad, we'll take it

Ian and Daniel's cousin Nicky, in a gesture that they won't forget, bought them Transformers (robots that turn into vehicles). He gave the dark greenish one to Ian and the bright yellow one, "Bumblebee", to Daniel. It turned out that the single difference in features, between the two of them, was that Bumblebee could make some fancy noise, whereas the green one couldn't make any, so of course Ian wanted to trade. Daniel, probably nowing that an "offer" to trade usually means the offerer has the inferior goods, refused reflexively.

However, Ian pointed out to Daniel - apparently accurately - that Bumblebee was the "good guy" and the green thing was the "bad guy." That was enough to make Daniel agree immediately to the trade.