The most interesting thing about colours is that they're not real. They're interpretations of light made by the human brain. Other creatures, with eyes very different from ours (such as bees), perceive the world very differently.
So when we say a colour represents something like joy or sadness or prosperity or revulsion, we ought to remember that those qualities are not in the colour. They're in us. And when we look at people and events and come to conclusions about them, often we are coming to conclusions about ourselves.
To truly understand reality, we must not forget the role our place in reality plays in our perception of it.
-