For me it depends on the person. For people i perceive as close-minded, judgmental or conceded, i tend to only share with them what i know will better my position in their mind.

For those who are genuinely concerned about me or interested in my thought process, i am a completely open book.

But in general, i feign my positive emotions fairly often. My sister emotes a lot, and i have learned from her how tone inflection and energy can really positively influence others perception of you.

It also depends on how much value i place on the person i am interacting with