While I don't think I am the person for whom you're looking, I will say that I always turn up my nose at ketchup () in favor of mustard. I eat my fries with mustard in the same manner that most eat their fries with ketchup or mayonnaise (double ). And, yes, sometimes (e.g. at the company cafeteria) the mustard of choice when I eat my fries is Grey Poupon.