Inside one department store the other day, I found it difficult to ask some customer service representatives some questions because I didn't know their name. It isn't as if I cannot talk to them if I do not know them (though that might be a reason) but there's something in knowing other people's names that makes us comfortable when talking to them.
When working for organizations or institutions whose work generally make you interact with people not part of the group, I think it is just natural that you and your coworkers be required to put up name tags. This is because of the obvious reason that there are people like me who find it awkward to directly speak to unknown personalities.
It's like during the first day of classes in your new school. Without knowing who your classmates are, you tend not to talk to them--unless you are an extrovert, something that I will envy if you ever are. I guess this is all about the sense of security, that even though you do not know each other well, they trust you enough to give you your name. Sounds mushy, no?
But like during the first day of classes, when your classmates fail to pin their name tags, you should still find a way to know who they are and what they know. Unless you want to become completely unknown, you do not have any choice but to deal with these unknown people. What's more in business? Nobody should be shy in business. That would be lost opportunities and money. Better get a psychologist to help you now--or just pin a name badge. That should be fine.