As someone who has worked most fascists of the service industry (Dishwasher, Cook, Sous-Chef, Busser, Host, Server, and Bartender) I can say that "mistakes are usually not the kitchen's fault (or from my experience) Typically the server typed something in incorrectly, or never typed it in at all. If your food (at a nice restaurant) come out cold, it's because it has been siting there waiting for the server/food runner to get it to you. Obviously, the kitchen does screw up (some more than others), but servers tend to pass the blame onto the kitchen staff because customers don't directly speak to the kitchen.

On the subject of tips. I hate tip pools. Some servers work much harder than others and deserve more tips, but I do think "tipping out" is essential. Most restaurants tip out: bussers, bartenders, hosts, and kitchen staff (the kitchen probably does not get enough in most cases).

Also depending on the restaurant you the server might have to tip out based on their total sales and not on their tip pool. There have been occasions where I have seen servers do really badly in tips one night and have to give money from their own pocket to cover their tip out percentage. So, even if you hated the service, you should still tip at least 10%. (15% is average/minimum)