Actually, I've often felt that the quiet folks are sometimes
very interesting folks... but they are like tortoises or snails, so
shy they keep putting their heads back into their shells!
But if you manage to draw them out, then, ah... you'll find that
they are really nice people. 
The loud folks, well, sometimes, the extroverts can be pretty
shallow folks. THey just wanna have a good time, be surrounded with
people, but they don't want any deep friendships nor
attachments.
Well, just my two cents' worth. 
