God created humanity and the whole world with so many different varieties, so many good things. God made so many types of vegetables and fragrances, flowers and thorns, dragons and horrors, to please humans and to keep them entertained. But humanity became more and more depressed.
Then God acted tough and humans had to start pleasing Him. So humans kept themselves busy pleasing God and they became happier since they had no time to get worried or depressed. When you have someone to please, it keeps you on your toes and you are happier. But if your goal is just to please yourself, depression is sure to follow.
Pleasure simply brings more craving but the problem is that we try to get contentment through pleasure. True contentment can only come through service.