This summer, I walked into a frozen yogurt store in Grand Rapids. It was open, but there was no one to serve me. Five minutes later, a young woman appeared, and said “it’s self-serve.” I picked up a cup, poured my own yogurt, then added a few toppings. But when I went to check out, to my surprise, there was a tip option on the screen. Despite the worker glancing down at the screen, I held resolutely to my decision: “no tip.”

While the social pressure is looming large to tip in more and more instances, don’t feel pressure to tip what the machine tells you to. Especially as college students, making wise financial decisions is more important than impressing the people behind you.

Over the past 10 years, the way we tip in the United States has changed dramatically. New technology is driving an influx of tips not only in the sit-down restaurant setting but also in non-conventional tipping environments, from coffee shops to liquor stores. New point-of-sale systems like Square and Stripe prompt customers to leave a tip, and suggest large percentages first, usually 20 to 25 percent.

This might not seem like a big deal to some folks, but if you get a coffee every weekday for $4, your 20 percent tips will add up to more than $200 a year on coffee alone.

But the worst part about the practice isn’t the amount given, it’s how some might be giving out of guilt, and others might be judging you for not giving as much. “Do you hit the ‘no tip’ button and brace yourself for inferior service from an insulted cashier?” a Today article asks. This is feeding off our omissions bias: the natural tendency to feel guilty when we make an active harmful decision versus an equally harmful omission, according to the Washington Post. Giving people a prompt to tip forces people to make a decision, and makes it feel morally wrong to skip a tip than if there was no prompt at all.

Square admits that its strategic software creates an uncomfortable spot for those who chose not to tip: “It’s one thing to bypass a tip jar or just leave the gratuity line blank when you are signing a check, but it’s harder to physically press a button saying you aren’t going to leave anything.”

A glaring iPad screen with pre-calculated tip prompts is a lot more intimidating than an old-fashioned tip jar, where someone can decide for himself how much to give on his own. You used to be able to give out of the graciousness of his own heart without the jar being shoved in your face every time you pay for something.

Even when you mean to leave a tip, electronic systems make it easier to overtip. Systems like Square have a pre-set tipping percentage that you program, and you have to choose another option to get to another price. So if you were thinking in your head of tipping $5 for something but the machine suggests $7, it is often more convenient just to go ahead and select what’s recommended even though you know you are overtipping.

Tipping a predetermined amount can lead to the unintended consequences of not distinguishing whether a person has done well or poorly in his work. It can also standardize tipping across different types of work that might not be the same.

For instance, I used to work at a gardening center that sold pre-cut Christmas trees. I would select the tree, bag it with netting, and freshly cut the stump, sometimes in the dark with the wind howling and the temperature dropping below 10 degrees Fahrenheit. In addition, I would have to tie it to a person’s car with numb, chapped hands before they could drive away.

I would argue that this type of work deserves a larger tip than simply ringing up your yogurt in an air-conditioned shop.

In addition, waiting on a table deserves a larger tip than passing you your coffee. Full-service restaurants rely on such gratuities since servers often are paid less than the federal minimum wage on the assumption they will earn tips, according to NerdWallet.

So tip generously when it’s appropriate, but choose your amount not because of what a machine says, but out of the wisdom and generosity of your heart.

Don’t be afraid of looking stingy, and don’t connect your self-image to the amount you tip.