The Grinch is an allegory illustrating that even just one loving person brings change to the world.

Cindy Loo Who is so loving she has no space in herself to process the Grinches evil. She still acts from love when he is revealing his cruel nature. Her unconditional love cracks open the veils over the Grinches heart. That feeling of pure love breaks the Grinch open and he can no longer bear his own cruelty.