If you don't like your job look for another!
My wife and I are both in the habit of tipping approx 5-6 dollars on a 30 dollar tab. We are very blessed to be able to do so. We frequent the same restaurants a lot and even make a point to tip extra to our favorite waitresses. On the other side of that, last Christmas I stopped at a Sonic for a drink and tipped the young lady the remainder of a 20. She took it from me and walked away without a word said. No thank you, Merry Christmas, nothing. Called a young man back to the truck there once also and asked him if he was still in school. He said yes so I gave him a 50. He was very grateful and was also one of the friendliest and by far the best fast food server we had ever encountered. A lot has to do with the attitude and Im just guessing that since you made a point to complain on here, that maybe either your attitude or quality of service to your customers may be the reason for the poor tipping.