Earlier quoted context omitted.
Years ago I collected all change for 6 months without spending any. Afterwards I counted all to see how much of each type of coin I have collected during this time. The idea was to see if it is worth bothering collecting all coins or is there are a cut-off for me as I dislike having carrying really thick and heavy wallet. It turned out that for my pattern of cash use collecting coins bellow 10 cents really wasn't wor…
When I pay with cash and the change would be below 5 cents, I usually say "Stimmt so" (i.e. "keep the change") and just leave. If I forget and the cashier puts change on the counter, I just pick the golden and silver coins and leave the rest lying there. I don't remember any unfriendly looks. But then again, I'm German, so I probably just didn't notice the looks. :)
The cashier's get into trouble if they have an incorrect amount of money in the counter and you're essentially telling them you're too good to bother putting the coins into the donations box sitting centimeters next to you.
If that isnt rude, I don't know what is.
This only applies to big discounters thought. The smallish shops and bakers don't mind at all.