According to Predictably Irrational, we humans only know what something is worth, or how much we like it, when comparing it to other similar things (e.g. purchases, partners, jobs, pets)

We tend to choose the middle option. A high price option on a restaurant menu increases average order price, because it makes the rest seem cheap in comparison.

If we have several difficult-to-compare items, but two are easily comparable and one of those two is clearly superior to the other, we will prefer that one to all the other options. Marketers sometimes even introduce a ‘decoy’ version of one item, slightly less appealing, so that the target item is chosen. In A versus B, introduce -A, and most people will choose B.