[vacuity]

Other people have given good insights, so I'll instead describe one of my pet theories.

Given by how we talk about emotions, I think they are "rational", but operate under a different set of rules than we normally apply to "rational" thinking. In fact, feelings are deeply intertwined with our supposedly "rational" thinking, to the point where I don't think there is a significant boundary. The lack of information is prevalent when feelings are in play, and I believe the same is true in general. Even physics feels far different than pure mathematics, after all. Instead of deferring to conventions in how to act when feelings are involved, as if they belong to a wholly different and mysterious world, we can make sense of the entire world. But of course, empathy, kindness, and good judgement are not exempt. None of this conflicts with what you're saying, but I think a subtle shift in mindset will be fruitful in applying it.

[n4r9]

Yes, I'd agree with that. The way I think of it is that emotions are somewhat "mechanistic". I don't directly control them, but they follow certain principles. For example, fear often arises in response to a perceived threat (physical or otherwise). My boss calling me to an unexpected meeting might make me panic. And even once the peak of the fear subsides, I am more vulnerable to experiencing it again for some time. E.g. I get home and my wife's car is gone, then suddenly I'm scared that she's been in an accident or something. None of this is a rational response. There are some hand-wavey evolutionary-psychology arguments for why they operate that way. But the main thing is that there are principles that make sense out of it, and those principles are (perhaps) surprisingly consistent across humans.

[Windchaser]

They're heuristics! Or "heuristical", if that makes sense. Simplified ways of processing the world, present even in creatures with significantly less cognitive capability and complexity, and bestowed to us via that ancestry.

And because they are very-simplified ways of processing information and provoking action, they often get things 'wrong'.