Would the world tend to be better, worse, or the same if people were more rational? If so, in what way(s) would it be better? If the same, why? If worse, why worse?
No.
Because we would not exist.
Our irrationality are strangely rational in the schema of survival. It's a survival trait that evolution gave to us, for
good reason.
Sure
assuming the sudden movement you see in the forest is a hostile predator is
not rational. But the rational person who waited for full verification and evidence of the movement's status as a predator
was eaten.
Our brains have evolved to make several shortcuts, especially when it comes to evaluating danger, that enables us to survive better overall. We're irrational
by design. Most animals that haven't been driven to extinction are.
Sure, we jump at sticks thinking irrationally that they are snakes, but
sometimes they are snakes and that irrational instinct saves us.
If humans were rational, we would have gone extinct before we got agriculture figured out.
All we really need is to foster awareness of
why we are irrational so we can work on a personal level to combat our own irrationality where it causes negative effects.
But human irrationality is still a
net positive, at least when it comes to our overall survival, otherwise
we would not have evolved in that way. If it was a detriment, then the irrational folks would have died and the rational ones lived to reproduce. But that didn't happen, instead the irrational ones survived.
And now that we have advanced to where we are now, we can start to understand our own irrational tendencies and work to minimize the downsides of this evolutionary survival trait.