As I say in a comment there, "Right in your own home, there's a Christian (however wonky) who believes that Hell likely is not purely metaphorical and is eternal (not infinite) but who isn't any unhappier for it." In that comment I discuss a little what I think makes the emotional difference.
Here I thought I'd talk about what I do believe about the afterlife.
First, by "purely metaphorical" I actually mean purely fictional, or a metaphor for some kind of psychological, social, and/or dharmic* punishment of evil behavior in this lifetime. One foundation of all my religious belief is that almost by definition, it's beyond human corporeal understanding and so pretty much everything we say about religion, God, and the afterlife is inherently metaphorical to some extent.
Also, while I accept Christianity as probably the best template for what I have experienced and learned about the afterlife, my views are open in that I think (in part because any description is metaphorical) that (1) no one really knows what's after death until, well, after death, and (2) our own consciousness will be so changed that even if we did experience that condition now, it wouldn't be the same experience.
With that in mind, though, I do think that the afterlife will be eternal: not an infinite extension of space and time as we know them, but an existence/perception without any limitations of space and time. This idea makes sense to me because time & space seem to me conditions of the body that need not apply to the incorporeal soul. I can barely imagine what this would be like, but Christian theology does address it; and fictional representations of eternity are one of the things that astound me some of the fiction of Charles Williams.
The way in which this afterlife could possibly be a Heaven or Hell is that I think that (1) choice is only possible in the face of time, and thus (2) whatever we are when we die, that's what we are in eternity. Now, I'm even less sure here than about the rest: I can theoretically accept the idea of some kind of change without choice, but I can't even conceive of it abstractly or metaphorically.
Of all the writings on Hell that I've read, I like best "We are punished not for our sins but by them." But that still implies some outside agent that could be merciful but instead decides to hurt us, even if it is us.
Laying this out in an orderly fashion now, I just realized that I have always assumed that an eternity of being an immoral person would be inherently unpleasant compared to an eternity of being a moral person. I do think this is true in two ways:
1) Union with God is always described as good and pleasant, so that being cut off from that is relative pain in itself. I do think that accords with what I know of union with God while I am still alive.
2) A lot of psychology shows that immoral people genuinely are less happy in some specific ways, including effects of the natural assumption that others are like you (a dishonest person generally distrusts others), lack of respect for those around you makes you less happy (the main ways for a dishonest person not to fear the marks is to think of them as beneath contempt), helping others decreases depression, and so on.
The version of God that I believe in definitely includes not only forgiveness for what we do, but also aid in doing better in the future. In fact, I think that a true prayer for forgiveness pretty much has to include a desire to do better & I believe that such desire is always encouraged and answered.
So at death, whatever we have done, I think we probably just have to live with that. As sturgeonslawyer pointed out (in a keen insight that was new to me), we live with the awful things we did and how we did better in the future, even made up for the awful things. Nothing goes away, good or bad. Hmm...I can also see how being a more forgiving person leads one to be able to accept eternity better, because of all the forgiving one must constantly do of others and oneself.
This belief system, although tentative, is not New Age fuzzy at all, and it does mean that some people will have a better afterlife & some much, much worse.
Sometimes I think that in eternity we can know everything, because of the lack of time & space, and this will be an added source of delight or torture. A murderer will not be told "you go to Hell for being a murderer," but will experience the pain and fear of hir victims, the grief of the victims' loved ones, the grief of hir own loved ones, and so on. And living one's entire life at once would probably mean being in the moment of making wrong choices while knowing they lead to such woe for oneself and others.
At the least, I do believe that if there is an afterlife, living in certain ways makes one more able to have a good or bad afterlife, and I do try to live in ways that prepare me well for death (inevitable) and the afterlife (which I find likely). I think my basic guidelines are more Christian than anything else, though I also find vital some aspects of Buddhist and gnostic thoughts that tell me to enjoy life but not become too attached to it.
Let me add, since turning 57 has suddenly made me feel much older, that I hope not to fully know for decades yet.
* Just helped a student with a college paper on the Ramayana and Mahabarata, and isn't that a better word than "karmic" for how most Westerners use "karmic"?
Mood: hungry, annoyed for reasons totally unrelated to this post or my bg