Answering questions fully and honestly means being vulnerable, and depending on a lot of societal norms, being vulnerable is frowned upon. Most people don't let themselves be vulnerable with anyone, or if they do, its only a few very close people that trust absolutely.
>and depending on a lot of societal norms,
I'm not sure I can accept that it's just social norms. It feels like a human universal. I really like honestly, and I often bend to social norms and avoid these kinds of topics. But for years, I falsely assumed that other people were like me: if we could just be past the initial fear everyone would be so happy to be able to speak so openly and honestly.
And unfortunately, this just is not the case. From what I can tell, for many, many people they just don't want to go there; they don't want to offer real answers to questions; they want the questions un-asked, or they want to answer with a socially-please lie, or a joke, or anything that changes the topic. I don't think we've been taught to be this way. I think we are this way.