I am not a painter. In fact I am really bad at using colours.
Whenever I see a painting a thought comes to my mind about the unlimited nature of our imagination, sentiments as against the limitedness of the canvas on which the painter represents his emotions. A canvas is more a kind of a snap shot of what the painter was feeling and experiencing within him/herself at the time when he/she was producing the piece of art. Can it actually be an exhaustive depiction of one's thoughts and feelings? Or rather to put it this way, if I am feeling joyous and decide to paint, can the end of the canvas put an end to my expression of this emotion of joy as well? I seriously doubt.
To draw an analogy with life. If I consider this life to be a canvas, then as any individual who is alive today, my aspirations, deep concerns, sentiments would be depicted on this canvas through my thoughts and activities. One day this canvas will suddenly get over without giving any clue to this painter(self in this case). Thats one difference that I see between this canvas and the painter's canvas.
The other difference that I can see is that with the end of this canvas of life, my thoughts and feelings will also end.
This makes me impatient to use all possible colours in the best way possible :)