positive impact on other people's lives
Having a valuable job allows you to positively influence the lives of others. It gives a sense of being needed and useful to society. Seeing the value in your work gives you a lot of energy to act and avoids professional burnout.
People with meaningful work are very committed to it. They put a lot of effort into what they do, but they get enormous satisfaction from it.
Finding a job that you deem valuable is not an easy task. Good knowledge of your own values is helpful here.