One point Sam Harris has made many times is to discredit the notion that religious adherents don’t really believe what they say they believe. I’m definitely guilty of that misconception, I’ve always felt that nobody actually believes their religious doctrines, not really. There may be elements and features of the belief system that are believed, and they might enjoy wishing some of it were real. But in their heart of hearts, everyone doubts.
Sam has repeatedly hammered home that that is simply wrong. There are true believers and they can be dangerous. A true belief in paradise is what allows for suicide bombers.
While watching Vikings and the Last Kingdom, I have noticed how much the clash of civilizations in those shows is about the clash of religions. The characters are constantly tormented trying to discern the desire of their particular gods and how to conduct themselves so as not to upset them, or win their favor. Each character interprets experiences in the context of their own religion, and their beliefs direct their actions. I do realize that these are just TV shows, and the intent of the writers may or may not be to comment on the nature of religious belief. Nevertheless, for me it did illustrate another example of peoples who actually believe, and how agonizing and all encompassing their belief systems can be.