Exactly. People can argue all day about how silly normalized middle-class tipping is (very silly, IMO), but the thing is that clicking a "20%" button isn't even tipping. The implementation of the buttons on the bottom of the screen is offensively out-of-touch with the actual tradition of tipping, making it even more transparent a cash-grab.

In addition to the fact that the POS button is often clicked before the service takes place and in the presence of the server, another key distinction of tipping is that it's off the books. It's a gift from me and a specific person providing service. If I pay through some POS machine it's a gift mediated through Visa and the IRS and the company payroll.

Tip only on credit cards. Otherwise you foot the bill twice.