Yesterday I went into a little French cafe in Portsmouth NH with a small grocery area in the front. I bought a shrink wrapped jar of mustard. Brought it to the

Yesterday I went into a little French cafe in Portsmouth NH with a small grocery area in the front. I bought a shrink wrapped jar of mustard. Brought it to the counter. Touchless transaction. I don't remember the tip options, but I don't believe they were above 20% or 25%. I made eye contact with the cashier and selected zero. I figure she didn't even notice the number I selected but I sure felt guilty doing it. But, why don't I feel guilty tipping 20% when I have a hand basket at the Market Basket with 80 dollars of food, or a grocery cart with 450 dollars of food in it?