maximisation, averaging and beauty
We mistakenly think of beauty as an edge case resulting from the maximisation of some complex parameters. This misconception has linguistic origins. (We say "very beautiful" and "very" implies a maximisation of some sort.) Beauty emerges not from a maximisation process but from an averaging one. That is why as more faces get pasted together using image editing tools, the resulting face looks more beautiful.
Our biological craving for normality has a sound basis since normality often implies healthiness. But when everyone craves for normality, the genetic pool quickly becomes a mono culture and this creates a vulnerability against new health threats. Hence there is a concurrent biological need for cross cultural genetic marriages as well. That is why the sweat of genetically furthest away people smells the best in blindfolded tests.
Combining the previous two observations, we conclude that what people crave for the most is the average of the furthest away genetic pool. In other words, beauty involves both a low-level averaging process and a high-level maximisation process.