To be happy: Eat & sleep well, be in motion all time, often go to see the mountains, the sun, the clouds and the sea, share life with great friends and do not ignore Love.
Or, as a famous Zen proverb says it:
“Before Enlightenment, chop wood and carry water. After Enlightenment, chop wood and carry water. That’s all.”
PS Also about work: do what you love and be happy just to do it, no matter the results.