alt Hacker NewsHaving an repulsion for shit is a healthy adaptation. But it seems that for some people they're much more sensitive.
Similarly, it's probably useful for a primitive person to vomit on sight of a familiar person vomiting, collective protection. Definitely a trait to find out before going to space!
The one I've never got is how so many people faint or become I'll when they see blood. Always seemed like a massive maladaptive that should create even more risk in a presumably dangerous situation. If a tiger attacks me in the night and the guy next to me faints because I'm getting eaten, we'll both end up dying.