Speaking for myself, I had the shocking experience of discovering that my own brain had 'malfunctioned' and that everything I had thought and believed to be real and true was a toxic illusion created in my malfunctioning mind. The "evidence" I had relied on was just subjective BS that my mind chose to leave, while ignoring whatever contradicted it. And of course I did not see this at all when I was doing it.
It's a truly shocking revelation to discover how fully one can deceive oneself. And while doing it, there being no possible way of detecting it. When our vulnerability is that profound, and that innate, there is no internal solution. And it's too confusing and frightening to just live with it. Faith is the only way through it. It may not even have to be faith in a "God", but it can't be faith in oneself. Because that delusion has been shattered.
Understanding this is the key to understanding theism as a way of life. And people that have never experienced it, both religious or atheist, very often have no idea what's really going on. Religiosity is often not faith based. It's just a form of self empowerment based on some intellectual sophistry. The same is true of most of the atheist scientism crowd. These are about creating and maintaining the illusion that the 'believer' is in control of their own fate. Whereas real faith is based on just the opposite. It's based on the shocking realization that the adherent is NOT in control of much of anything. Such that faith is the only option left to them as a way of moving forward. But keep in mind that faith is trust and hope being ACTED upon. It is not sitting passively and waiting for some 'higher power' to take care of us.