http://www.youtube.com/watch?v=rT-_Sim2AbM
As art progresses exaggeration became very important part of it. I think even today we see exaggeration in Art everywhere. Because that type of art attract us more than simple original art. Movies like Spiderman, Hulk, and Batman show us unrealistic human forms which are not at all possible. In some fashion show they wear clothes which make model look gorgeous but actually those clothes are not wearable. At some gardens or public places, they prefer unrealistic human figures for statues. It is our tendency to find more human than human in arts which lead us to this form of art.