Here's part of an explanation I've liked for a long time: they're a product of developing cognitive processes that bias the brain to model the world with supernatural shortcuts.
(Moved below the fold because the silly video defaults to autoplay.)
More like this
If there is one thing I hate with a burning, red-hot passion in a website/blog/whatever, it's content that autoplays when I access a site.
Gosh. I hope no one looking for Ken Ham's Ark Encounter accidentally types arkencounters.com.
(Warning! Obnoxious autoplay video! Warning! Dinosaur porn! Warning!)
Freaking hilarious! Nothing to do with the brain though - ohh well. Don't play this out loud at work - it's a bit potty mouthed. (Sorry for the autostart - I can't figure out how to not let it automatically start).
I don't think they do, but a few certainly do their best to taint the whole.