I believe in the afterlife.
I also believe that humans have the unconscious ability to influence their relative perception of time. Think of all the times that seemed to "fly by," or moments that "last forever." I think you do this unknowingly, and it's usually connected to a heightened emotional state, which means you have an increased level of some neurochemical. I don't think there's a specific one responsible for altering our perception of time, just that they correlate.
That we have the ability to alter our perception of time is what allows us to have an "afterlife."
What I believe, without evidence, is that when you die, your brain does a massive dump of all of it's dopamine and serotonin, as well everything else, that let's your final moment be one of peace and acceptance. Additionally, you will stretch your final moments till it seems a lifetime, all while hallucinating massively because of this huge dump of neurochemicals into your neocortex.
So during your final moments, whether you believe you're going to a heaven or a hell, you're right. Because that's exactly where you'll imagine yourself. If you think you'll bounce around a field of billowy clouds while visiting loved ones with all your pets by your side, then you will. If you think you deserve to drown in a river of hellfire while the world laughs, then you will.
As an athiest, it kinda gives me something to look forward to. One final hurrah before nothingness.