The subject of tipping in restaurants has come up recently, and I realized I had a heuristic for such things. This seems a good as place as to write it down.
If I have to stand in line and order at a counter, there's not going to be any tip.
Caveat: if (a) there's a tip bucket and (b) I've been there before and (c) the food was really good, I'll drop a dollar in the tip bucket.
Base tip rate is 15%.
If the wait staff is rude, the tip goes down. (I don't care about your shitty day. Be professional.)
If the wait staff is impossible to find, the tip goes down. (I can't serve myself, else I wouldn't need you.)
If the wait staff continually interrupts, the tip goes down. (I didn't come here to listen to you talk.)
If the wait staff makes excuses, the tip goes down. (Your team, your problems. Take up intra-staff conflicts with your manager.)
If the food isn't very good for the class of restaurant, the tip goes down. (Again, your team, your problem. Reward your cooks. They're why I came.)
If the food is late, the tip goes down. (Again, your team, your problem.)
If I end up thirsty, the tip goes down. (I am not going to reward you for ensuring I have a crappy dining experience.)
If the bill comes with 'pre-computed' tip-guide based on the post-tax total instead of the pre-tax subtotal, the tip goes down. (Your establishment is trying to scam me. I resent that.)
If the wait staff seems to be actually enjoying their work, the tip goes up. (If you're enjoying yourself, you're helping me to enjoy myself.)
If the wait staff is nearby often enough so that when I need something, they're there to help, the tip goes up. (Making my experience pleasant should be rewarded.)
If I never have to ask for a refill of my beverage and water, the tip goes up. (If you're going above and beyond, so will I.)
If the food is better than expected for that class of restaurant, the tip goes up. (I came here for the food. I hope you share your tips.)
Generally, it's pretty dang easy to get to 20%, and you have to basically be phoning it in to get 10%. Note that I round the final result to a dollar amount, and the percentage of the tip is based on the pre-tax subtotal (since the government gets the tax, it's not part of the food or service price).
All this excludes significant problems. The quality of a restaurant's service is not really in its day-to-day service, but in how they handle dining disasters -- did you forget or drop my dish? Did you get the order wrong? Does what's delivered not match the menu? Was something under- or over- cooked? Did the food go bad? Was there something _in_ the food that shouldn't be there? These sorts of problems eventually crop up at any restaurant, and this is where I really start to pay attention to how they're resolved.
Do they apologize? (If you don't apologize, you're not sorry, so that means this is expected or that you don't care. Either way, bad.)
Do they make excuses? (Excuses are bad. They don't fix the problem. They don't make things right. They just waste my time and your time.)
Do they get the manager involved? (Better, but it indicates that you don't have the authority to make things right, or you don't have a policy of how to make things right.)
Do they not charge me for the item? (Minimum expected behavior. If you don't do this, I'm likely not coming back, or if I do, 10% is the tip ceiling.)
Do they not charge me for any of my meal? (Good! I had a bad experience, but at least it didn't cost me anything.)
Do they not charge me for any of my meal and give me something extra (e.g., a dessert)? (Great! I had a bad experience, but it didn't cost me, and you demonstrated that you were actually sorry about it. I will strive to become a regular, and will suggest your establishment whenever folks wonder where to go to eat.)
Do they not charge my party at all? (Awesome! Your establishment is so committed to superb service that they'll eat the cost of a screw up. That's dedication. I will be back. I want to send all of my friends to your place, because it's a guaranteed good time. I will make friends with strangers for an excuse to introduce new people to your place.)
If I have to push for something to be done, or ask the the manager, or make a fuss... that's a failure. The wait staff has just ruined my experience by Not Doing Their Job. I will be unhappy. I do not like to be unhappy. I do not want to be unhappy. My unhappiness will be expressed in my tip, and in future choices, and in how I describe the establishment to friends, acquaintances, and outright strangers.
Some common objections when I float (bits of) the above in conversations:
"If they're slammed, you have to take that into account."
No, I do not. It's not my fault that the manager didn't allocate enough staff to serve the people he let in. Hire more or better staff (you may need to pay them better). Increase the size of the kitchen and decrease the size of the seating area.
"It's a hard job."
It's part of the job. Do the job, or do something else. Paying someone to NOT do their job is incredibly stupid.
"They might be having a bad day."
Yes, and so might I. I went out and GAVE SOMEONE MONEY so I could have a better day, and they made it worse. And kept my money. I assure you, me spending money to make a bad day worse is in no way a better experience than someone *getting* money for having a bad day.