Just remember, evolution operates by natural selection trimming away (killing off, before they can reproduce) the variants (individuals) that are less fit to survive in a given environment. Fitness is not necessarily equivalent to goodness. Qualities like honesty, philanthropy, or resistance to superstition do not always carry a selective advantage. And after billions of years of evolution, here we are.

@Flyingsaucesir Fitness isn’t necessarily yes/no but a matter of how many descendants result versus other conspecifics.

In smaller groups the traits passed to descendants become more based on intergenerational shuffling of the deck or sampling representation than being beneficial or detrimental. If people with a tendency to polydactyly just happen to be amongst a remnant population, polydactyly will become more common in future generations without much to say for that trait being related strongly to fitness.

Some behavioral quirks, such as religion, could result from having a larger brain that facilitates baseless speculation. One can see patterns that don’t exist in the way presumed and such superstition can become popular for arbitrary reasons, such as carriers being more gregarious or influential over a group.

@Scott321 Right, it's complicated. To the extent that any behavior is genetically-based, it is almost certainly the result of the expression of many genes in concert; the term biologists use is "polygenic traits." And then there is the effect that environmental conditions can have on the expression of genes, the study of which is a field called "epigenetics." It sounds like you have a pretty good grasp of the situation, and I'm not telling you anything you don't already know. I'm glad you steered the conversation in this direction. It's essential to recognize the complexity here. There are no simple answers.