The time I was yelled at, btw, was for giving 3 quarters as a tip for a $3 cup of coffee. "It would have been more polite" to give a whole dollar, and not as change, but as a dollar bill, I was informed (by some other customer). OK, but I don't have another dollar bill, and I really don't care to carry around those three quarters...
I did try for a few days to have an extra dollar and tip with that (carefully saving up the change for use in wishing wells)... but nobody said thank you or anything, so I gave up. If I have to go to a lot of effort to give someone money and they don't care, eventually I am going to get tired of doing it. And I did. (Did one person ruin it for everyone? Yup.)