Once some spirits eager to explore what heavenly joy was like were granted the opportunity to perceive the deepest level of their own joy, up to the point where they could no longer stand it. It was not angelic joy and barely resembled even the least of such joys, as I could tell when their joy was communicated to me. It was so paltry as to seem rather cold. Still, they pronounced it most heavenly, since it was the deepest of their own joys. This experience showed not only that there are different levels but also that the deepest level of one kind barely extends to the shallowest or middle level of another. It demonstrated further that when we gain our most profound joy, we are in our own heavenly joy; we cannot bear any deeper variety, which would only end up turning painful for us.
A group admitted into the innocent state of the first heaven spoke to me from there and confessed that the condition of that heaven was so glad and joyful that it could never be imagined in the least. This was in merely the first heaven. There are three heavens, and each enjoys a state of innocence, with all its countless variations.
from Secrets of Heaven, Volume 1, Sections 543, 544