If you ask a buddhist monk, such as Geshi Tashi Tsering, he would explain what happens in the afterlife in terms of karma and the emotions we go through when we are actually in the stages of death:
“If one is going to take a lower rebirth, very strong, fearful appearances will appear to your mind during the dissolution of the four physical elements. Conversely, in a fortunate migration, more gentle appearances occur and there is a happiness in the mind. During the radiant white sky, red sky, etc, visions there are no particular fears because the coarse conceptions do not arise.
“The way of dying affects your emotional state at the time of death and this determines which karmas are activated. For example, if someone was killing you, you might become angry, and this would activate a negative potency, a condition for a bad rebirth. It would require a very strong practice of tolerance not to get angry. In general, we should make efforts to help the sick, elderly and dying to generate a very healthy, positive state of mind before and during death. This, in turn, will benefit us, helping us to continue our work towards helping others.”
But as far as people’s personal beliefs about heaven and hell—they are just that. Nothing more than beliefs (have not been proven) and personal (based on their fears of the dissolution of the person they believe they are). No one whom I’ve talked to, who has ever had a death or near-death experience, has ever mentioned hell. Particularly the version of hell with the devil poking them with a flaming pitchfork.
Conversely, no one mentions the bland version of heaven, with angels playing harps all day in the clouds, that certain cultures indoctrinate into their people. So, despite people’s beliefs that they have “earned” this sort of heaven, anyone who has returned from the grave has not vouched for this depiction of the after life. It is a much more dynamic process that goes beyond the petty conjectures of the human mind.