[wongarsu]

>Being good at business is, in large part, only serving profitable customers.

I strongly disagree with that notion. Even if you know in advance who will be profitable, you often gain more customers by servicing all customers (or at least the vast majority).

Two examples:

1. A lot of internet companies are built on servicing everyone, and extracting money from a tiny subset (github is one example).

2. If one in every thousand customers costs me more in support than they pay, that's one thing. But becoming known for good support will be more profitable than becoming known for kicking customers who ask too many questions.