Not to yuck these peoples' yums, but why would they choose these food combos? The ones included below are truly odd — and chefs and waiters were the ones telling on their customers. The r/KitchenConfidential community answered the question, “What are the grossest substitutions you’ve been asked to make?” Interestingly, the OP suggested that they were unhappy with a customer substituting mustard instead of apple butter on a sandwich with sourdough bread, cheese, and bacon. Tons of commenters sco…