There are many expectations, quotations, and assumptions about life. Life is short, enjoy it. Work hard to have better life. Don’t expect anything from life just accept what it offers. And there are many more, all these might be correct, but they might not be valid for everyone and for every situation.
Few people might work hard, and they might not be able to achieve the success they deserve. Few may think they are unlucky; few may think they might not have required capabilities. Few people are never satisfied though they have everything to cover their needs and comforts. Few people are so content with the basic needs.

There is no equation for success, happiness as I believe. As long as one is content, there is no other success or a goal to achieve, but it’s very hard to be content in all situations.