If something is undercooked,I do quietly ask for it to be cooked some more. If there is a real problem with my meal I will usually say quietly,politely when it is served If on the other hand,I get the shoulder shrug,rudeness or indifference I make sure I put it on every available forum and advise others not to go there. I do tend to work on a. 3 strikes and you,'re out system. Like if I ate somewhere and the food isn't good,if someone asked us to a do or dinner there I would still go. I believe in customer service, mistakes happen for lots of reasons. It's all about you making the customer feel valued,apologising goes a long way too.