The NF is driven, above all, by his almost indefinable need to grow in a way true to himself. Part of that growth includes the process of finding the self. In a nutshell, the NF pursues the goal of becoming.
The NF temperament is complex and difficult to understand. Whereas the other three temperament types can understand (though perhaps not approve of) one another, none really understands the NF's craving for constant change in the pursuit of finally discovering the real, true self. Only NFs themselves know the commitment to a goal in constant flux.
Finding their prototype in Apollo, NFs walk the earth full of passion, seeking intense relationships in the process of becoming their true, ideal selves. If they can help the rest of the world find themselves, then all is well. Ironically, for NFs the path to self-identity is often in helping others discover their own truths. NFs hunger to help, but in the larger, more spiritual sense rather than the specific, duty-oriented sense experienced by SJs.