It's not totally uncommon to place an order at a fast food restaurant and later discover the workers had made a mistake or two while delivering your food, like adding pickles to your burger or forgetting you wanted Diet Coke instead of regular. These mistakes are a little annoying, but overall they aren't that big of a deal. After all, mistakes happen.
But when you're given the completely wrong order on purpose, that's when you're entitled to be a little more upset, especially if it leads to you eating something you normally wouldn't, like real beef.