I think the greatest happiness someone can feel is when you see you've made happy the people around you, you've made them feel something.
When I work in an app/web release, or I present a film, or when playing in a concert, the most important thing for me is to think there are people on the other side, and that what you are giving helps them feel in some way.
The book "Inspired", from Marty Cagan, says 'emotions are the most important thing: the user experience serves the emotions, the software serves the user experience, and the hardware serves the software.' The optimal organisation of
elements (hardware/software/UX, images/sound, instruments) is the key to touch people's emotions from a product (with a web/app, a movie or a song).
I feel very grateful to work in my day to day with great professionals (finance, business, technology, design, marketing, communication, legal, operations, customer service...) organising all the elements we have for "delivering value". At
the end, what we do is respond to people who are in front o a product, motivated by a need, where you have the opportunity to impact in their feelings.