Your attitude is like a box of crayons that color your world. Constantly color your picture gray, and your picture will always be bleak. Try adding some bright colors to the picture by including humor, and your picture begins to lighten up.

This quote means that your outlook on life is like a box of crayons that color the world around you. If all the colors you choose are grey, the world will appear dull and gloomy. Instead, if you add some brighter colors by being happy and funny, then the world will become brighter and more enjoyable.