Question

why are humans so fallible??

Answer 1

So long as humans have a good working brain they will continue to be fallible. Choices are made through a variety of ways and all of which are susceptible to various cognitive biases. Through these such things can be determined like:

I'm okay, I don't need to see a doctor.

The doctor says that I only have a 13% chance of getting cancer, but that's okay as I've got a 87% of being just fine.

I've got one week until my project is due, but since it's all worked out in my head I can relax for a few days first because this behavior worked out just fine the last time and I know what I'm doing.

This specific course of action I'm taking must be correct because while I'm not quite sure yet myself, everyone else around me is convinced it's the best choice to make.

I know myself well along with the world. My views and beliefs are rock solid and while I may not have any proof of it, I do know that this other person is completely wrong in theirs.