Selfishness & Self-Centeredness
It is interesting how our language is quite accurate when it comes to the sense of "I" (delusion) and the realization of no "I" (awakening).
We talk about selfishness and self-centeredness, both of which come out of a sense of "I". And we talk about selflessness, which is the true nature of what is and effortlessly revealed when there is a realization of no "I".
In the first case, there may be what appears as selfless living, but this is most often only appearances. It comes from trying to align ourselves with an idea of selflessness, with one pole of the selfish-selfless polarity. It still is filtered through the belief in the idea of "I" as a segment of what is, it still comes through the idea of I and other.
In the second case, there is an immediate realization of what is with no "I" anywhere. The content may be exactly the same as before, although no revealed as just a field with no "I" in any of its segments. The only "I" is the whole of what is - God, Buddha Mind, Tao, Brahman, Spirit, that which is beyond and includes any and all polarities, and it still functions through this particular human self.
The nature of what is is selflessness. And when what is awakens to its own nature, this is effortlessly expressed and lived through this particular human self.