Why Are We Like This?

Often I'll meet someone who (for example) is footloose and fancy-free, and when asked to reflect on that will attribute it (say) to having parents who moved countries a lot as a kid, and therefore never really settling down, and therefore now (as an adult) being very unattached to things.

And this makes sense as a story, but it also strikes me that the opposite story would equally make sense: your parents moved around a lot, and therefore as an adult you got married and bought a house and stayed in the same place for the rest of your life.

And therefore to me it seems like the "real" cause for this person's personality is actually something else: something about this person made them react to the childhood-moving by becoming footloose, instead of by becoming stationary, and really that's the interesting part of the story.

Many (most?) of the stories people tell about themselves have this format to me:

Why are you so rule-bound and studious? "Because my parents were very strict." Ok, but surely other people have reacted to the same kinds of rule-boundness by becoming wild and rebellious?

Why do you think you care so much about fairness? "Because I experienced great unfairness in life." Ok, but some people experience unfairness and respond by thinking "screw it, I guess it's a dog-eat-dog world so I'm gonna go eat the other dogs".

I've never been much of a life story guy – I am illegible to my own eyes, I cannot explain Why I Am Like This even to myself, and this causality-attribution issue is one of my core complaints: I don't think we know why we are how we are, and the stories people tell about it are largely unconvincing to me. Sometimes I think it's Bad to be so non-narrative, that people are happier when they have a coherent life story whether or not it's true, and would be better off ignoring the question I ask here. If so: sorry!