Cuteness

How humans decided which animals they want to eat heavily relied upon the cuteness of said animals. Just take for example rabbits and chickens. Rabbits are insanely good at reproducing. They are however also extremely cute. Chickens are good at reproducing. Adult chickens however aren't as cute as rabbits.

Thus the reason humans systematically breed insane amounts of chickens just to eat and don't do that with rabbits.

This is basically the main criteria to separate pets from food.