If your customers are demanding, be thankful.
Instead of just asking 'How did I do?' ask 'How can I do more?'
Compromise in your arguments, not in your expectations.
The right measure is not how many customers you've got, but how closely you hold them.
What matters more? What you said you'd do, what you hoped to do, or what you did?
There's no such thing as the very best. If you're doing your best, it's only because you haven't yet found a way to do better.