I see nothing wrong with people who have nothing to say.. Or if they do have something to say someone interrupts them..
sometimes it is also a psychochatic disorder. Now look at this image that the person use as a signature. The image is a person with the throat full of blood and probably dead. Don't you think that the person is murdurous, have hidden motives, not trusting and need to see a psychologst. etc? Like most of the psycho serial killers are quiet.
I think it goes back to your upbringing, too, when, especially in Asian families, your relatives say "oh, what a good child, he/she's being so quiet" and being quiet is a sign of being respectful. I find that when it's my job to speak to people, I really have no problem, but otherwise I tend to keep to myself unless I'm really comfortable with everyone that I'm talking to.