Human Beings are greedy and selfish. Nothing is ever enough. You will want more and more and more.....
Health or Wealth.
When you are poor, you desire for wealth. You thought you will be happy once you are rich. But when you are rich, you thought you will be happy only when you are rich and healthy. When you are rich and healthy, you found out that you have a damn ugly wife and desire for someone 's wife who is so pretty. When you are rich, healthy and have a chio bou wife - you found out nobody respect you for your life achievements and is still unhappy.
The point is nothing is ever enough, you will always found something to be dissatisfied with life. One will always dream of turning back the clock to change the regrets in his life not realizing that nothing is ever perfect in life.