Happiness is there. It goes nowhere. Just take off your eyes covering and see every God's gifts around you.
It is better to be content with little that we have rather than always struggling for more. It's like chasing the wind. Everything has its own time, and everything will come in time too. We do our best and the best thing that we can get is be happy and enjoy ourselves as long as we live.
Wise men and foolish men will have the same end. It indeed seems useless for being wise or hardworking because we gain nothing in the end. The difference between them is the process while they are living. It's like living in light is better than living in darkness. But the main thing is to keep the joy in everything that we do, which are gifts from God.
When you set up a purpose or an achievement that you want to make in your life, don't run in order to get there. If you run, you won't get the chance to see everything around you, then you'll fail because you forget to consider people and things that out of your plan that lay around you. If you run, and say that you make it there, there is no point that you get there because you are not happy for your whole life. You just get your happiness for a while when you get what you want and you forget what is that for. You lost the main thing.
God wants all people to eat, drink and be happy in their work which are gifts from God., that is the main thing. Everything from God will last forever. That the way it is since the beginning and it will continue to be that way. What has happened will happen again.