Work and live to serve others, to leave the world a little better than you found it and garner for yourself as much peace of mind as you can. This is happiness. ↗
After all, I long to be in America again, nay, if I can go home to return no more to Europe, it seems to me that I shall ever enjoy more peace of mind, and even Physical comfort than I can meet with in any portion of the world beside. ↗
You find that you have peace of mind and can enjoy yourself, get more sleep, and rest when you know that it was a one hundred percent effort that you gave - win or lose. ↗