Well, if we were right all the time, life would be very boring. There would be no surprises, and no questions worth asking.
We know less about how the human brain works than we do about stars and the universe. So trying to figure out exactly how the brain produces behaviour is *very* complicated.
If we think the brain does something in a a particular way (‘method z’), and an experiment shows that it doesn’t, it doesn’t just mean we’re wrong – it means we have to re-think many things that have lead to this moment. So we don’t just look at ‘z’, we need to look at ‘y’, and maybe even ‘x’.
So when I’m wrong, it may something much more interesting about the world, than if I’m right 🙂