This act of human nature arouses the image of a water painting:
People behave like the ways of colours, where each shade is different to one another. When we combine/converse with a new person, a new side (colour) is unleashed in us which is why we never have a constant personality. This act corresponds to the way specific colours respond to one another - they forge a new colour. There is no such thing as 'showing your true colours', for a new colour is shone through you every time you meet a new person.
It's like our world is a painting constructed of water colours - all twisted together. Or even kind of like a paintball fight on a grand scale.