Brains evolved from the material available, to serve some basic purposes: improve chances of survival and reproduction. Brains were not designed and don’t have “UX.” What each of us experience is an emergent property, or side-effect, of the brain’s evolution.
The concept of rationality is a human invention (like morality). Neither are inherent properties of the brain, they are learned behaviors and social constructs.
You're not owed a good experience, or a healthy brain, or a nice life. There isn't a manager to complain to. I'm sorry.
> Why is it so hard to change ones ways?
So hard like what? If it is rational to change then you change, otherwise you don't. Have I just missed something?