It is easier, and more cost effective, to keep current customer than it is to find new ones. That being said, so many business owners and sales people fail to realize it. Customer service is crucial in keeping AND gaining clients. You can never be too comfortable with a client and believe that they won't leave you. Or that they'll understand where you are coming from.
They don't care. They care about their needs and getting them met. If you don't go the extra mile the once in a while that they ask you to, they'll find someone who will.
No kidding. I hear business owners tell stories about how their customers ask them for a rush job, or special circumstance. And instead of doing it willingly, they decline - and expect their client to understand. Heed my words, they don't understand. They'll get their current problem solved elsewhere and then start the process of replacing you with a vendor who cares about them and is willing to service them; even when it's inconvenient.