We only seem “irrational” when we are talking about a narrow view of “rationality”, i.e., as defined by the cold hard logic of machines. We do not question why we have this definition of rationality. Our “irrationality” simply seems so because we have not bothered to understand the larger complexity of our evolutionary programming. It’s the same as not bothering to understand how a car works, and then claiming that the car works on magic. If one understands how it works, then it is no longer magic. In the case of humans, we may never fully understand how we work, but we can work towards a compassionate understanding of the same.
/rant
You can, as a human, map the 'wrong' response to external stimuli resulting in, say, your death (or the deaths of your progeny, for that matter)
If something seems irrational, that's because there are rational things layered on top of one another in a way that creates a misapprehension in a partially-informed observer.
Why? You assume nature must be comprehensible to us because you define it that way? Nature's not under any obligation to us.
> If something seems irrational, that's because there are rational things layered on top of one another in a way that creates a misapprehension in a partially-informed observer.
Possible irrational things: Collapse of the wave function, consciousness, why anything exists. There's also non-computable functions, paradoxes like the liar paradox, and the inability to refute various skeptical possibilities like living in a simulation.
Combine that with the fact that all models are wrong, some are just more useful. We can't model the entire universe with perfect accuracy without the model being the universe, which means there are always things left out. Our rational explanations are approximations.
