This photo (of a CVS worker taking a personal call) accompanies Seth's post related to customer service...or, the lack of it.
The best reason I can give as to why people don't provide great customer service is because they don't want to. The roots are of course much deeper than that. You can find those here. But, on the surface, it's really simple...you either want to care for someone and are interested in how they feel...or, you're not.