Interesting that you should mention Purgatory. Jesus never mentioned it and it was rejected by Protestants in the Reformation. I suspect, at least in Luther's case, the rejection was because the concept was essential to the sale of indulgences, which was the origin of his dispute with Rome. (The indulgences were sold to build St. Peter's Basilica.)

Personally, I find the concept of Purgatory to be psychologically useful. As applied to myself, I don't think I am good enough to go to heaven but hope I am not bad enough for hell. As applied to others, I want them punished but not for eternity. I realize though, that God's justice is beyond our understanding and think "retributive justice" may be something we want because of our limited understanding.