Depends on what they got wrong. If it's simply forgetting to add or take off something as long as it's something I'll still eat I'll take it. Same if I had gotten something different than what I asked. If they forgot an item though, I'll go back and kindly ask for the item with receipt in hand.
I'm veeerrry patient and I don't really ever complain since I work said industry and I've been on the receiving end of really rude customers one too many times that I would never want to be the reason why someone's day is awful. Mistakes happen and often enough they will replace, remake, or whatever it is that they gotta do to fix it, so why not just... be nice about it?