This story proves one of the adages I live by: A person who is nice to you but rude to the waiter (or in this case sales assistant) is not a nice person.

Instead of compulsory military service, if I were world dictator, I'd introduce a scheme whereby everyone - including rich people - would have to spend time working in a customer facing service job of some kind. Why? Because I believe it instils a permanent respect for people in those professions, and they thoroughly deserve it (I worked a Saturday job in a supermarket during my A Levels, and took a number of similar jobs during my university years).