My hubby puts ketchup and mayo on pizza. My son puts mayo on steak and cheese grinders. I think both are disgusting.
One thing I thought was the strangest..about 6 - 7 years ago, I was out to breakfast with a friend and she ordered French Toast. When it came, she poured maple syrup all over it! In my 30+ years (at the time!) I had never seen such a thing. (I later found out almost everyone does it!) I was raised with only putting butter on french toast.
Anyway..I tried it and MMMMmmm. I called my mom right away and told her she deprived me as a child!