I've definitely been in more than a few restaurants where I feel like I was gypped. I usually just don't eat the food, and when servers ask me if everything was OK, I tell them it wasn't and just pay my bill and be on my merry way.
A good restaurant will want to make it up to you and either give you a discount or comp the meal. If they don't though it's no big deal, I look at it this way: I paid for a dinner to know, for certain, that a restaurant is bad and to never go there again. I kind of do that with certain people. If I don't want to hang out or interact with them, I let them borrow money, then I never have to hear from them till they pay it back. It's perfect.
Some people, however, feel like unsatisfactory restaurant service is a crime. A huge crime, apparently for this guy who was so upset about this size of his dinner that he called 911. Twice.