[Chelbe]

I agree. Don't let it stress you or ruin your day.
I've done that type of work before and when that would happen to me, as someone else stated, I would place their change back on the counter the same way they handed it to me and go on about my day. I also agree with you too, it does make it difficult to be so pleasant to the next customer, but don't let it get to you. I hate nothing more than to be pissed off at a person who in the long run means nothing to me, but that's just me.

Now, if I was the customer, I have said something to a cashier who could take my money out of my hand, but place or throw my change on the counter. I was never rude, just bold about it.