Sorting through some old papers I came across a notice that used to be pinned up in the shop that I worked in. It reads :
Our customer is the most important visitor to our premises.
They are not dependent on us, we are on them.
They are not an interpretation of our work, they are the purpose of it.
They are not an outsider of our business, they are part of it.
We are not doing them a favour by serving them, they are doing us a favour by giving us the opportunity to do so.
I think it would not be a bad thing to have this pinned up in a few shops I go to.