I'm laughing as I think 19-20%--outside of very big cities servers are lucky to get 15%!! Of course I know YOU all give 20% or more when you tip (Can I laugh now or later?)
Okay where do I start? Are you aware that in most cases, especially with corporate owned chains, the server doesn't get the charged tip until 10-14 days later? Did you know that many restaurants charge the credit card fee to the server? Oh, that's not legal? Okay complain to the boss and in a right to work State you will find yourself let go because in a right to work State you can be fired without reason so don't complain so you can have some money coming in--that is in addition, like in Florida, to the $3.60 an hour you get paid. Don't like working off the clock or coming in for 'meetings' or having to vacuum floors or clean chandeliers and not getting paid because you are getting served a sandwich and soda---or getting 50% off the price--or how about getting your hours cut so they can save on benefits?
Let's get something clear--I LOVED being a server and I was a professional one who, as a rule, had many call parties wherever I worked but from 1956 when I started as a server even the best boss I ever had thought 'waiters are a dime a dozen' and they still think so! I took pride in being a server and made good money at the job. I didn't like 'sidework'--that is work like filling salt and pepper shakers, wrapping silverware, cleaning salad bars and refrigerators, sweeping floors, 'marrying' ketchup (which is illegal), mustard, A-1 sauce, etc., for what in the 1980s, 1990s, was about $2.50 an hour because in many cases your couldn't wait on customers at the same time--and it was/is all legal in a right to work State.
As a young waiter I was foolish in the sense that I wanted to party so I wasn't about to declare a lot in tips--finally in my 50s I started to declare 20% so at least I got a bit of social security (though it mainly came from my Memphis income). In the 1990s restaurants started to automatically declare your tip earnings as 15% of your sales whether you made it or not. By tipping cash the server has money for every day expenses, pays taxes and gets social security.
Most people don't realize that servers 'share' their money: 15% to bus people, a share to bartenders, a percentage to food runners who in turn would rather get cash tips now instead of on their check later when it won't cover their expenses.
I could keep on going about why cash instead of charge tips but another example--and it has to do with my having to stop working--with charged tips I had to pay more rent which could be $75 more a month and that was just working 2 nights a week.
Two additional things: when leaving a cash tip put it in the hand of the server--I have seen wives pick up tips that husbands left (and, yes, I said something to them, quietly asking if I could speak to them a minute) and I have seen servers steal other server's tips.
Last, but not least, if you don't want to tip 15-20% then stay out of full service restaurants--stay home, serve yourself, wash your own dishes or go to fast food places.
PS If you are smart you would pay your bill in cash, too--you never know who will copy your credit card number and use it for themselves--sad to say but true!