What makes heaven desirable?
Why is hell horrible?
All those who believe in an existence after this earthly life desire that it be a good one. Heaven is our concept of that good existence, and hell is its opposite. Why would we desire heaven? And what makes hell so undesirable?
Answer
All relationships are built on common value systems. A perfect relationship would require perfect agreement in value systems. Improved relationships come from growing together in value systems.
The value system of God is sacrificial love for the benefit of others, and our native value system is selfish love for the benefit of me. Since all conflict in relationship is conflict over value systems, this puts us in conflict with God. It also puts us in conflict with all others because the object of everyone's love (self) is different.
There is only one God, but God is composed of three persons. Each one of them has the exact same value system. Therefore, God is an inherently relational being and exists continuously in perfect relationship. Heaven is the place where God exists and where only his values are lived. (Matthew 6:10)
Heaven is not a physical place like this earth. We know this because God is a spiritual being and God's Kingdom is not a physical kingdom. We don't have much information about hell, but there is no indication that hell is a physical place either.
Earth is a physical place, and (Biblical and practical) evidence is that the physical realm distracts us from the spiritual realm. This distraction is strong enough that many people completely misplace their need for the spiritual. Some even misplace their need for good relationships.
Relationships are a spiritual issue because of their basis in value systems. This physical world diverts us from the critical importance of good relationships because it can anesthetize our loneliness with its interesting distractions. However, when we pass out of this physical world, those distractions will be gone and the full effects of loneliness will be able to be felt.
There is only one place after this physical life where good relationships exist (because of shared values), and that is heaven. Good relationships banish loneliness, and in heaven where the value system of God is the only value system, loneliness does not exist. For social beings like ourselves, this is the most desirable place.
Whatever other option of existence outside of heaven after this physical life will be a place of utter loneliness. This is because no one in that realm will share values. That option is a hell. This hell always continues to be hell because the only value systems that exist there cause deep conflict between people. There won't be friends in hell because everyone will only be thinking of themselves. And since our physical world with its distractions is also missing in hell, there is nothing to help anyone forget their loneliness.
The curious thing is that since heaven and hell are non-physical places, they can also exist on this earth. Therefore for those who are in God's Kingdom, they have already entered an aspect of heaven. The effects are greatly muted by the distractions of the physical realm, but for us heaven and hell are both present and future.
The value system perspective used here is based on ideas from the work of Darren Twa.