Over the years, whenever reporters would ask him the secret to Southwest's success, Mr. Kelleher had a stock response. "You have to treat your employees like customers," he told Fortune in 2001. "When you treat them right, then they will treat your outside customers right. That has been a powerful competitive weapon for us."...
"There isn't any customer satisfaction without employee satisfaction," said Gordon Bethune, the former chief executive of Continental Airlines, and an old friend of Mr. Kelleher's. "He recognized that good employee relations would affect the bottom line. He knew that having employees who wanted to do a good job would drive revenue and lower costs."
I've worked at more than my share of offices in the past dozen years, and I think there may be something in this. Watch out if you've got customer-facing employees who don't answer internal colleague emails, are rude or curt to peers in their organization, promise stuff but don't deliver, hold onto information for their own advancement rather than the sake of the team. You probably also have a customer relations problem at the very least. Is this person answering customer email or calls politely? Sharing customer problems with other people who can help? Looking for help in solving the problems that the customer has?
Then look at the tools your employees have to use... if you find crappy tools in use internally, then double check that this isn't exposed to customers in some form. The MathWorks has an internal usability group that works on design and development processes for corporate tools. I think it pays off in many ways, not all of them related to internal efficiency. It's a sign of respect for your staff to give them the best tools to work with.
If you hire well, trust your employees, and give them a reasonable job to do, they can be your strongest advocates for hiring, referrals, and posting nicely about you in their blogs! And they'll go the extra mile on the job. Besides, a lot of your employees, past and future, are customers too.