How does colour work in Animation?

Phil suggested me to watch the Animation The Lady and the Reaper a wonderful example of how colour can work so much in an animation. This is basically a 'chasing' animation for the old lady's soul between the surgeons and the Reaper. The vivid colours suggest the chaos that was taking place in the Animation and kept changing from one colour to another, making the whole story very effective.

I could give thousand of examples of 'colour magic' in animations but the first one that comes in mind is one of the scenes in Disney's Tarzan (1999). The colour blue is used very often throughout the film in the jungle scenes, a colour that symbolises home, tranquillity, safety and family. Suddenly, the gorillas get attacked by the hunters: the scene turns bright red and everyone's in panic. The sudden mood swing of the scene was  symbolised by the contrast of the two colours: from tranquillity to chaos.

The quiet blue scene...

...turns into a shocking red one.

For my own Animatic, I am aiming to use a lot of COLOUR which will assist my chasing/running scenes just like in The Lady and The Reaper.