Personally, I experience the greatest degree of pleasure in having contact with works of art. They furnish me with happy feelings of an intensity that I cannot derive from other sources.
When my cats aren't happy, I'm not happy. Not because I care about their mood but because I know they're just sitting there thinking up ways to get even.
At the door of every happy person there should be a man with a hammer whose knock would serve as a constant reminder of the existence of unfortunate people.