The truly successful have found happiness in what they have. This doesn't mean we can't continue to strive for doing more, doing different, being better or changing the world, though they will all be easier to do when we attack them from a happy mindset.
We spend so much time rushing around and trying to make things better that we often forget to enjoy what we have. We need to have goals and dreams, but the chase for them should not include ignoring today. By being present in the moment and finding joy in what we do, we are giving ourselves the fuel to continue to push forward. When we start to believe that happiness will be around the next corner or it will appear when we reach our next goal, we are setting ourselves up to constantly chase something we will never catch. Find the happiness in what you have and then start making change because it is what you want to do, not because you think it will make you happy.