A posting just reminded me of a relative's eating rituals. I'm not sure if "rituals" is the correct term.

How common is it for people to insist that different foods do not touch one another on the plate? Is it common for people to eat only one food at a time from their plate? Is it common for people to refuse to eat mixtures of foods they like?

Its common for me. I cant have any of my stuff touching each other. Fortunately my wife is awesome and she understands. I only eat plain things, one thing at a time. (I can still wear my clothes from high school -- what's wrong with that)

Eat drink and be merry. It all lies in the presentation.