Are you working for other's approval? Lao Tzu once said "If you look to others for fulfillment, you will never truly be fulfilled." The idea here is that we can work hard and not make other people happy because we can't control how other people will react.
So when you're working on a task, give it your best effort. Take time to understand what others are looking for and deliver the best you can. At the end of the day though, your happiness can only come from within.