Moderation In Modernity

What is the relationship between success and happiness? Are the two inevitably intertwined?  I can think of plenty of people who are successful and incredibly unhappy, and yet of all the happy people I know, they are all successful in their minds even if they don't meet society's definition of success (namely financial, but nowadays celebrity status also appears to a measure of success - how many followers do you have, how many likes on social media, etc.).  How do we achieve this level of happiness, or more specifically, what is the key that these individuals have discovered towards being happy in all circumstances? Apparently I am much better at asking questions than finding solutions; however, after some contemplation over the weekend I've come to the conclusion that happiness is related to confidence, and confidence comes from not letting others' opinions influence your sense of self-worth.  Seems pretty straightforward, right?  I've always been much better at...