Okay, my number one rule is no blood in the library. But aside from that I have a few general rules:
2. We don't work at the "no" factory. The first response isn't "we can't do that". Try and find the "yes" if possible without infringing on another patron. Some staff took this at first that we never say no. That's not a blanket yes to more computer time if someone else is waiting. It's not a blanket yes to extending a summer reading book when there is a holds list. But, is there really a reason why someone cannot have a special check-out period for Huck Finn while they are sailing on the Mississippi?
3. Take the money. Cousin Fred checked out a book using Cousin Beatrice's card. Fred racked-up the late fines, but doesn't have Beatrice's card. He wants to pay the fines. Take the money. Give Fred the cash register receipt. Save the account receipt for Beatrice. Don't inconvenience them both.
4. This isn't the cosmetics counter at the local department store. Don't chase people to make the sale. "May I help you find anything?" "No, I'm just browsing." "Okay, if I can help please let me know." Give people privacy and the gift of time to look.
5. No weltschmerz. Well thought out complaints are fine. General whining is not.