People tend to like what’s familiar. The statistically average facial features are, then, pretty darn familiar.  If you look at “composite faces”, or faces combined together, the end result tends to be pretty attractive. The results of what is attractive were from American studies. There are slightly different cultural preferences, but those are generally the desirable features.

Another study was pretty interesting. In it, a picture of the given person was taken and then transformed into the opposite gender, without telling them. The participant was then shown the picture, and they would then rank that picture highly. People are attracted to themselves!