I've been on both sides.
I used to be uncompromisingly tacit, reticent, and silent. I rarely said anything to anyone, and I was in the position where you were "doing me a favor" to talk to me.
Question peoples maturity, that woud work on me, though no one ever did it.
A lot of it hast to do with a lack of self condifence, things like that - as far as the quiet one goes.
BUt now, sometimes i feel like I am drawing blood from a stone sometimes. Bottom line - make an issue of respect.
If you are trying to hold a conversation with someone, the least they could do is return the effort back and be interactive.
If not, let he/she know that you are being disrespected, and that that is not cool