From COLOURlovers, here's a neat article on 13 color legends. For instance, take the origin of envy as a green monster:
Color associations vary greatly from culture to culture, just as each language or dialect has unique colloquialisms that are often misunderstood or lost in translation. In many Western cultures the feelings of envy or jealousy are commonly associated with the color green. [...]
This association first appeared in the seventh century B.C., according to etymologists Judith S. Neaman and Carole G. Silver, as the poet Sappho described a stricken lover’s appearance as “green.” At that time the words “green” and “pale” were often used interchangeably.
Other literary figures followed suit. The familiar expression “green-eyed monster” was adopted from a line in Shakespeare’s play Othello:
O, beware, my lord, of jealousy;
It is the green-ey’d monster which doth mock
The meat it feeds on.
Similarly, in his play Anthony and Cleopatra, Shakespeare described envy as “the green sickness.”
Previously on Neatorama: Reasons for the Colors of Everyday Things