My thoughts are my thoughts. I share what I choose to, and the rest is mine. Don't quiz me, demand to know what I'm thinking, tell me I'm meant to share. I have a right to privacy. Don't assume that because you want to share everything with me, that I should want to share everything with you. Don't present your view of the world as the only possible option, and that I must be somehow emotionally stunted, wrong, or hiding something.
If I haven't told you how I feel about something, it's probably because I haven't decided how I feel about it. I can't make decisions without all the information, and I don't offer solutions without understanding the problem.
If you want to get into the mind of an introvert, this short piece will get you there.