Fuck if I know in Random bits of it

I became very aware awhile ago how much time I spend day dreaming. Not so much detached from reality but you know how you’ll run a hypothetical situation through your head occasionally? (disclaimer, I don’t know how often people do this, I just feel like I over do it) I feel like that takes up 90% of my time. Every person I pass, every situation laid before me, I just wander off in my head bending the situation so far from reality it would be unrecognizable if I had to explain it. Now I’m no mental health professional but this seems like a sort of defense mechanism turned coping agent, but I’ve been this way for as long as I can remember. Even as a child I was called out for being quiet, not contributing to the discourse, whether it be with family, friends, classmates, etc.
I was always in my mind, behind or ahead but never really present. It can negatively effect potential relationships, work someone up in your head to be something they’re not, then when they don’t meet that unrealistic expectation it upsets. Same thing applies to jobs, moving new places, trying new things, it’s trouble managing expectation at its core I guess. I just want to know why I do it, why can’t I be more present in conversation, why can’t I just have a realistic expectation for life? For all situations? Is that something you can work towards? Tempering expectations to align with reality? Who am I even asking? Maybe it’s symptomatic of a raw unhappiness with reality, after all I’ve never been accused of being a happy go lucky fellow. I tend to lean on the cynical side, calling myself a realist but knowing I’m more pessimistic and not because I have some deeper understanding of the world, or think myself too intelligent to turn a blind eye to the grim, but that’s just the way my brain functions. I have to try really hard to solicit happiness chemicals on my own, with others it’s easier, maybe a codependency issue with positive feelings.
I feel like the ability to look inward, to understand the passage of time, to have mortality is what makes us special but I wish it was an opt-out sort of deal. It’s too much sometimes.