You may "believe" in Maslow's hierarchy, but whether it is truth is certainly up for debate. Even the "Criticisms" section on the Wikipedia page you link has plenty of legitimate debate. As with most psychology, it is a soft science at best and pseudoscience at worst.

Through your own missions work, you must have certainly met plenty of people (or at least heard plenty of stories) of people possessing far less on that hierarchy than the average American who were far more content and held an "actualized" attitude about life.

The very highest definition of love (Greek - agape), often denotes self-sacrifice, something that certainly goes against the grain of an ego-driven desire for personal happiness. I'm sure you know it all too well as a parent and the many sacrifices you make for your kids =) I think we live too much of our lives worrying with an inward focus when the real answer is to take that energy and turn our focus outward to others. Self-centered may have been a harsh word, but it is what it is.