The difference between Lain's path and Haruhi's path demonstrate totally different worldviews.
Lain's worldview is a selfless one, as if there is something greater than her worth sacrificing herself for. This is most closely related to Christianity, as can be assumed from the Christian themes and imagery throughout the show. To lay down oneself not for the greater good, but for something greater than the self, is righteous and admirable. This is why Jesus did not resist the Romans as they captured him, beat him, and crucified him. Selflessness is admirable because it involves doing something to the benefit of other people or other tribes at the detriment of one's self or one's tribe. There is nothing tangible to be gained, yet there is still gain from it. Moral fulfilment is often achieved through selflessness.
On the contrary, Haruhi's worldview is very self-centred. While she may have rejected the role of God, she lives in such a way that everything must revolve around her. She rejected the role of God because she felt appreciated. We can assume that she would have embraced the restart of the universe if she did not feel any appreciation from someone she valued. This worldview ironically lends itself to atheism and the rejection of something greater than reality.
RE: Lain Iwakura and Haruhi Suzumiya: a parallel journey as gods