How do you live life to the fullest?

I think my mother's friend, Uncle William, is a person who lives life fully. Although he doesn't have extremely much money, but he has a happy family and a stable work. He lives in the US and has a house which is not too small or too big. Both of his children went to good colleges and have good grades, so that he don't need to worry about them and he often go on family trips in the states. I don't think a person needs to have great achievements to live his or her life fully. Instead, I think a full life is to have a stable income, a happy family, a comfortable house, can travel to places, and don't need to worry about his children. Having these things means that one don't need to worry about anything and can do whatever one wants, and I don't think there are any downsides for these experiences.