1-2% report a hellish realm in the immediate post-death experience, though it may be under-reported. You could say the same for heavenly experiences (ie. under-reported).
What happens is the newly dead state is that expectations are manifested immediately. So if there's fear, you experience hell. If there's peace, you experience heaven. The newly dead very quickly realize that the environment is a hi-fi reflection of their thoughts, so they change them to something pleasant and boom!... everything changes.
It's the same in the living state. Our expectations are reflected in our environment and circumstances. The difference is that there's a delay. In both states, positive thoughts are more powerful than negative.
