I try to be kind, upbeat, etc in my interactions with other people, especially at work. I want to treat others well, work together peacefully, and leave the project happy. I’ve noticed that some people (particularly more curmudgeonly folks) seem to read that attitude as naïveté, and feel like they can walk all over me or treat me like I don’t know what I’m talking about. Why is that?
There are many things at play in situations such as you describe. One of which is often a form of jealousy “I don’t feel happy, so you shouldn’t either”. People often don’t even realize they do this, sub conscious.
They probably don’t intend to be negative, just haven’t found a way to better be.