Have been in the hospitality industry for 14 years. Bartended, Served, Hosted, Cooked, fuck bussing, Managed. If your server sucks, fuck 'em. Don't tip them shit. The world is full of shitty waiters/waitresses, don't promote that behavior. After cooking, I have zero respect for most tipped positions thanks to seeing what type of work they actually do. Your server deserves a tip when they keep you happy all night and no less. If they give you 50%, give them 0%. Bottom line.
Bartenders make retarded amounts of money for very little effort, but they also put up with drunks. I tip a dollar a drink unless I've already ponied up 30+ in tips for an average night. If they are taking care of me like instantaneously? I tip better. If I am put in the line like everyone else? After a bit they are effectively cut off. When I tended bar, you take care of the people who tip you, and everyone else gets Normal Mode. Which is generally first come first serve unless someone I was taking care of was up. Always take care of your tippers, or they stop tipping. I like to reinforce those trends.
This. I'm a pretty generous tipper; I feel bad if I leave anything less than 20%, and like others have said, that can go up depending on extraordinary service, or things like weather for delivery guys.
Having both cook and been a hostess in the hospitality industry, you really get to understand the type of people who aren't doing their job, who are doing just what is expected, and those who go above and beyond.
When I was a hostess I worked at a four star restaurant in the middle of the city's cultural district - this meant a lot of high rollers who would tip me $50 dollars for hanging up their coat. But I loved talking to people, and would go above and beyond for my awesome regular customers, or people who just felt genuine. We were once booked up full on a busy night (Cultural district busy night was usually if opera/symphony/ballet or a convention were all going at the same time..those nights were crazy) and I had a couple call in who really wanted to get a table that night. I told them we were totally booked, but I felt for them...it was their first night off since they'd just had a newborn (And I am certain they weren't lying) so even though we weren't supposed to do it, I took their information down and said I'd see what I could do.
A little bit later, I worked a bit on time management, and between people coming early/late, found them a table and called them back a bit later. When they came in, they were super excited, tipped me $20 (which I refused, told them I wouldn't take money for doing my job, but when they suggested I give it to the bus boys or something if i truly didn't want it, I took it. Our bus boys did jack) and became regulars who I always found spots for. Another time I had a guy call me from overseas in the military - he wanted to make a reservation for his parents anniversary, but didn't know much about the restaurant. I got his email address, took a picture of the restaurant, emailed that to him along with our menu. When his parents came in, they were ecstatic, knew me by name because of the service I'd given to their son, and that actually started a long friendship.
Anyways, those anecdotes were just to show that there are legitimate people who belong in an industry working with people, who should, at least get a baseline tip, but probably deserve more. That same restaurant also was home to a ton of servers who did jack and shit and were assholes on top of it. Since we were such a high class restaurant, we also had crazy good wines, and as a rule servers made bank because of how much you had to tip on a good bottle of wine. And they never deserved it.
Don't become a server etc if you don't like people, or don't want to take care of someone how you want to be taken care of. That chick at applebee's I feel for, because it didn't seem like she didn't do her job, just that the person really wanted to stick it to her. Bottomline gratuities for large parties I always pay, because even if your server isn't going above and beyond, taking care of large parties is crazy work. Admittedly, if the person is truly fucking up you can always speak to the manager and lower their tip, but I've seen that happen so rarely.
So yea. 20% as base if I feel they are doing their job. I feel like everyone should work in the industry just to understand some things - I'm much more patient than I used to be in restaurants because now I can understand things, and that's made quite a bit of difference.