well, there are plenty of idioms and superstitions..

like "salt of the earth" to define a good person (some one valuable to have around?)

or "take things with a pinch of salt" (just as salt improves flavor, you should improve your outlook?)

(or are there better defination/ different understanding of the idioms?)

or that spilling salt is bad luck, and if you do spill it, you have to gather up a pinch of it, and throw it over your left shoulder to rid your self of the bad luck.

any others?