9. Now we really don't have a problem tipping for good service, and we are fully aware that service staff in the US rely on tips to make up for low wages; but we found it offensive to suggest a gratuity of that level for a very ordinary buffet - where nothing at all was prepared fresh for us, no-one took an order from us, or brought anything to the table for us and other than a busboy filling our coffee there was no other actual 'service' involved.