“stiffing people” is language that implies they are entitled to the tip, which they are not as it’s a tip. Expecting a tip is falling victim to the propaganda that enables employers to maintain low wages. By continuing to tip because “that’s what people do” you’re only further cementing this culture.

If more people refrained from tipping or tipping excessively when not appropriate, then employers would have to increase wages. That’s how to solve the problem.

When I tip, I tip 20%, but I’m not going to begin tipping at a grocery store or getting a coffee unless it’s a small, local establishment.