One of the worst parts about being a server, but also one of the most humbling, is taking the blame for other peoples' mistakes. When the kitchen messes up and it isn't your fault, when the hostess forgets to assign you a table (then when you do finally get the table the patrons are pissed), or when the bus boys don't clear your table so you have to. All of these things are ultimately your responsibility because your table is your table. You get all of the blame, but only some of the rewards. This is because of the 'tip out' system, which I believe someone mentioned upthread.
But aren't we supposed to tip on the overall quality of the meal? If the kitchen is constantly screwing up orders and costing a server money, maybe he/she should look for work at a restaurant with a decent kitchen staff?
Regardless, since we're only tipping the waiter/waitress, we try to tip just based on that person's performance. Just bringing out an underdone steak wouldn't (shouldn't) be enough to justify a lower tip...but if you took 30 minutes to give us menus, then another 60 minutes to get the food to us (food that looks like it'd been under the warming lights for a while), and don't come back within 3-5 minutes to make sure the food is edible...ok, that's not all the kitchen's fault. If you're on top of things, and try to fix any mistakes that pop up, we can be awfully forgiving.
My wife said at one restaurant she was made to take out food even if it was obviously not cooked correctly (say, a burned steak). She'd do so, let the customer know that she had to bring it out, and tell them she could take it right back and get another. Odd thing, that restaurant didn't stay in business much longer, though she still managed decent tips.
The tip out is the percent taken out of your sales each night to pay the hosts, bus boys, cooks, and food runners. Let's assume the tip out is 3% on each table. So, let's say that I have a table where the final bill is $100. The service was fine, but they had to send the steak back because it wasn't cooked enough (kitchen's fault - I said well done on the order). That left them upset, so they tip only 10% instead of a nice 20%. The tip that is left is $10. But $3 automatically goes to the tip-out pool, so I keep $7. Had the tip been a nice 20%, I would have made $17 with the tip-out still being $3.
But that shouldn't be the customer's problem. If the customer is expected to tip based on the waitress's performance, and the waitress gives abysmal service...why should the customer worry how it'll affect the waitress?
BTW, I don't like the tip-out custom at all. All these people are getting at least minimum wage. I think it started out as a simple bribe (in a system where no one tips the bus boy, if you're a waitress and start tipping him "out of pure kindness", I bet he'll make sure your tables are always the first ones cleaned and ready for more customers). Eventually it became expected, and now it's virtually mandatory.
I guess with all the "mandatory" tip-outs the servers have to do...I can almost forgive the recent creeping up of the tip percentage. Really doesn't excuse the jump from 10-15% (since I don't believe tip-outs were as mandatory then, if even a thing), but I can understand going from 15-20% (though I'm so set in my ways, I'll probably keep tipping 15% for "did the basic duties of the job" service).
Next time anyone thinks about getting up without paying, think about what you are really doing to the server. My opinion is that unless someone is actively trying to make me have a bad experience, or I see them spit in my food, etc. etc..., then I'm paying for the meal and leaving a tip.
It would depend on the situation. We've left before without paying for the food we ordered...but never after the food had already been brought to the table. In my mind, once the food's brought to me, then I am obligated to pay for it, even if I hate it (manager may agree to comp the meal...but if he/she doesn't, I'm not walking out without paying). An obvious exception would be if they brought the wrong meal out (so if I order steak and they bring fish...I would feel no remorse if I got up and left). Now...since we virtually always order a soda, this makes a quick getaway impossible; rather, we get up, find somewhere to pay for the drinks, have to explain why we're leaving, then go. This doesn't happen often (last time I can remember was years and years ago, we'd waited over an hour, got up to pay for our drinks, was told the food was suddenly ready, but I said nope...waited long enough, we're leaving).