Do you complain to waiters/whoever when the service or food is bad? Any interesting experiances related to this topic?

Inspired by the meal with my step-mum and dad last night. They were already drunk when they picked me up to go out for dinner. Between us we drank four bottles of wine and I didn't have all that much, so they were pretty drunkered by the end of the meal. We got a cheese plate and the Brie was rock hard (the waiter didn't even know that it was meant to be soft and my step-mum tries to do an impression of how it usually ozzes out the side with some butter!). They proceeded to complain to the manager of the whole hotel, who looked about twelve years old. My dad nicknamed him 'the embryo' (to his face!). And despite two other tables in the restaurant complaining about us and the noise we were making (we were laughing a lot and carrying on a bit), we still managed to get the entire meal for free. Jammy!