> One's circumstances are seldom that much dependent upon their beliefs about the world.
You are interpreting belief in a very narrow and mysterious way. If you believe that poison is food, or that bus impacts are healthy, then you are going to have a bad time. There are many beliefs that must be correct in order to ensure survival. It isn't all relative.
>There are many beliefs that must be correct in order to ensure survival
Or you could say, you know, that beliefs must hold some utility. There are a lot of utilities that we need from our beliefs. I believe that the front of the bus is a portal to hell that threatens to damn me to eternal suffering, so I'm quite terrified when it approaches to engulf me. This shares utility with realizing that an impact with a bus can result in awesome momentum transfer, causing a sudden acceleration preventing my soft body from containing my precious bodily fluids. The point is the utility, not the rationalization (this term is loaded pretty heavy at this point, sorry).
I would argue that most religious people technically have a belief about the world that is false in the usual definition, and many of them are having a great time, especially since their religion gives them a nice little life manual.
If your beliefs about the world are entirely false then you are going to have a bad time.