> 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?
By UX of the human brain, I mean the experience of being a human.
Your example of rationality is a great one, let's assume an ideal human being is one who optimises for rationality. Why isn't rationality innate in being human? I'm sure to a degree it is, but I think you'd agree that the world could be a little more rational, and perhaps even you yourself could be (I certainly could be).
To speak further to my experience, there's things I rationally know I should or shouldn't do. But I don't act accordingly always (or often - depending on my mindset).
I'm sure I'm not the only one who finds the endeavour of making rational changes difficult? And rationality is just one aspect of 'human-brain UX'.
A little example from my experience: I know that programming on Lisp is kind of one of the most rational things I (as the citizen of world, not as a greedy egoist) can do, especially if the result will be a FOSS software. But also I need to spend time to: sleeping, eating, cleaning my body and house, earning money, having rest after workday, having travels for having bigger chunks of rest, having rest after that travelling, having some another duties... Am I not rational? Potential users of my (unreleased) FOSS application might think that I can be a lot more rational than I use to be, but some other people can say I am enough rational, especial if I have an ability to think about all of that. Maybe your problem is very different from mine, but please do not forget that you do have a lot of rationality which seems to be so rational that you even can not think about it (because it is also rational!)
Hope my example helps you to look at your problem from another angle.