I bet it happens with everyone "First impression is wrong impression" . Generally what I have seen is what I am writing.
Most of the time, in initial talks you see some people less talkative and not so user friendly but I am damn sure in long run they are going to be your good friend. Just give one minute break to your mind and think of your good friends, good friends of same sex. If its a matter of different sex, equation is complete different and I don't want to go further on that.
Some guys/gals you find in the initial meet very talkative but after 5 or 6 month, you feel him complete different from your initial experience. I have a valid reason to define my point. Silent person believes first on time then on knowledge. His mindset says: Let me take sometime then I will show you what I know. Whereas more talkative person which people generally feels more smart and dashing believes on knowledge and then time. His mindset says: Let me impress this guy first, afterward I will manage.
Both approach is correct. This is my personnel option. So no crimes. May be some crap !