I believe some superstitions were rolled out only so that a lay man could simply follow them without having to understand the nitty-gritty of the reasoning behind them.
Or it might just be a statistically observed fact for which a scientific basis was discovered later.
A simple example being:
"Do not disturb plants in night. They are sleeping."
"A ghost sleeps on the tree at nights."
Plants inhale oxygen and exhale carbon dioxide in night. The low levels of oxygen might suffocate you for example in a closed room.
Or am I just retrofitting things?