They tell themselves that they have achieved happiness but it is so blatantly obvious they are the saddest, hopeless cynics half way down a slippery slope and picking up speed.
I have seen (and heard) the same from people. They are bitter, even while they are telling people about how great life is. It is similar to the people who in one breath talk about how they like being overweight - whilst they look jealously at people who are in better shape than themselves.
I think I have a similar outlook to you - there is value in some kind of service to others for me. I want to feel like I am adding something, not just taking up space.