Interesting concept: no heaven or hell. The afterlife is living your life all over again, but from the "perspective" of everyone you ever interacted with. Beat up some guy on the streets when you were 23? Guess who will be waiting for you on that faithful day, when you're 23. On the other hand, if you were beaten up when you were 21, your revenge will come. 21 years after your death, perhaps, but it will come. Same for good experiences. That good thing you did? Shall be done unto you in the afterlife
Similar concept which I take no credit for, but enjoyed very much:
All humans are but one person living over and over, but with no memory of their past lives. Everything you've ever done, you did to yourself. You were Mother Teresa, you were Gandhi, you were Pol Pot. Every injustice perpetrated upon you was committed by yourself, and so was every kindness. One day the universe will end and you'll re-integrate all your memories.
I personally believe that if there is an afterlife, you're the one responsible for how happy or punished you are. Everyone goes to the same place, but they experience different levels of comfort based on their own assessment of their life. This happens at a deep enough level that you can't lie to yourself about it.
Other than the psychopath angle, there's also those who are mentally ill and/or delusional and believe they're terrible people when they're not far off average, maybe even better.
Likewise, perfectionists, but maybe I'm repeating myself.
Got to hope that you're not right for their sake.
Personally, I'm hoping for oblivion. Like it was for the billions of years before I was conceived, I assume, not that it's possible to remember that.