Maybe I'm just mega autistic or something but whenever I'm lore building in my world particularly around cultural practices and why people in that tribe do certain things.

I'm vary detailed because I have an obsession with history and particularly cultural studies of early humans which is super fascinating to me and because of that, if I feel like something is a little bit too much fantasy I basically throw it out to where most people wouldn't even think about it.

In my opinion every unique thing that a tribe or primitive society does.

Is either due to a misguided belief or a purely practical tool that later became outdated and abstracted into something fun and interesting like a festival or something that still serves a very real functional / purpose.