Imagine it: seasons changing without colour. Holidays with no bright decorations. Colourless birthday cakes, fruit salad, ice cream, M&M's and Skittles! Without colour, life would look pretty bleak and boring, but in order to fully answer this question you have to first understand what colour actually is.
Basically, when you see a colour what you are really seeing is different types of light bouncing off things. Light travels in waves of varying sizes called... wait for it... wavelengths! Some light may have longer wavelengths, while others have shorter ones, with each wavelength representing a colour. Usually, these wavelengths travel as white light, but once they hit an object the light will bend and separate into different colours. Some wavelengths get absorbed by the object, while others are reflected off of it which is what we see as colour.
So, in the end, without light we would have no colour, which would make the world a very dark place indeed.