Sounds a bit like the Golden Rule—and I guess it is. This is obvious: If I treat EVERY service provider as my CUSTOMER (even when they are having a bad day) ... then I radically increase the odds of getting good-great service from my "customer." This notion is a first-class "Duh," but it struck me anew yesterday. I went into an electronics shop and badly needed help. The only clerk in the store is in no danger of winning the "employee of the month" award. Yet I showered him with love & affection, as it were, and got an unfair share of his time-attention; in the end he offered pretty damn good advice. (Moreover I didn't let the little prick ruin MY day! And he actually wasn't a L.P., he was mostly left holding the bag by his manager—perhaps a B.P.)
Hence my "golden rule" du jour: My service provider is my customer. To get good service give good service to those who service you.
As I said: Duh!