When dish does not taste good, I usually don't complain about directly. Not showing any superficial response, I resolve to myself, I'm never going to visit this restaurant again. If I receive a wrong food at a restaurant, first thing I do is asking a server whether this dish is served properly. In most cases, it's a simple serving mistake and can simply fixed by asking them. However, there are circumstances when my order was practically delivered differently. If this is the case, I mention about what I had ordered and show little discomfort about situation, but I still took the dish that has been wrongly served. In most of the cases I didn't have to pay for the dish that was served in mistake. Dealing in this way is efficient, because it's waste of time to wait for the food that ordered again, and I'm getting a free meal despite the inconvenience.