To understand hell, one first has to understand God’s nature. Since He’s the One who created it, you need to ask yourself what was on His mind when He did so. First of all, hell was designed for Satan and his angels, not us. After the Fall of Man, however, the human race became included in the package:
He will also say to those on His left, “Depart from Me, accursed ones, into the eternal fire which has been prepared for the devil and his angels.” (Matt 25:41)
Secondly, God does not “torture” people; He punishes them accordingly for the evil they do. Take the law of gravity as an example. When you fall off a cliff and get killed or break a bone, you are suffering the consequence of breaking that law. God takes no pleasure when that happens, even though He authored the law. Jump from the roof of your house and you’ll reap the “punishment” of trying to break gravity’s law—perhaps a broken ankle. Take a swan dive from a 70-story skyscraper, however, and breaking that same law will be fatal.
The same is true for moral laws. Breaking a moral law has consequences that occur as a result of the violation. Since God is a moral being, immoral behavior rouses His anger. A person doesn’t have to answer at the Judgment as to why they jumped off a cliff. They will, however, have to answer for acts of fornication, adultery and so forth. Why is this so? Because those things affect other peoples’ lives—people made in the image and likeness of their Creator.
The wages of sin is death. (Romans 6:23) The harder you work at doing wrong, the fatter the “paycheck” you’ll receive in the end. You “earn” death by committing sin. If that sin is not forgiven, it will be held against you at the Judgment. This is why it’s so important to give yourself over to Jesus. After all, He took the punishment that you deserve for the sins you committed.
Third, God is perfect. He doesn’t make mistakes. When He designed us, He didn’t have a “recall” and fix something that He overlooked or goofed up on. For example, the earth was originally designed as a perfect biosphere, able to recycle and repair itself and supply us with almost anything we can think of. This total perfection also translates over to His love and justice. Even His hate is perfect, not tainted by cruelty or loss of emotional control. A person will reap what they sow. (Galatians 6:7) They are not going to be unfairly punished.
I don’t think it's fair that people go to hell.
A curious thing to note is found in the story of the Rich Man and Lazarus. (Luke 16:19ff) When the rich man sees Lazarus in Paradise, he asks if Lazarus can bring him some water. He does not ask to be released from the flames. In the same way, people want to be where they feel comfortable. They also connect the place to the situation with which they’ve become involved. For example, a perfectly healthy person wouldn’t want to spend two weeks in the hospital. In fact, you’d demand to be let out. Hospitals are for the sick. Healthy people don’t want to be in a hospital. Yet the sick aren’t happy to be there either. The same goes for prison. If you were unjustly incarcerated, you’d demand release. The guilty person, however, knows they’re in jail for a reason. Like the sick person in the hospital, they may not like it, but they understand the legitimacy of being there.
How does this translate into heaven and hell? Heaven is a place of perfect harmony and love. My understanding of the Bible is that the intimacy that will exist in heaven will be beyond description. The apostle Paul was shown heaven, where “he heard inexpressible things, things that man is not permitted to tell.” (2 Cor 12:4) To put a self-centered or mean-spirited person in such an environment would be a nightmare for both him and those around him. In hell, however, they’ll have the “benefit” of total isolation from God and other beings. They won’t like it, but it will be compatible with what they are.
Why does a person have to spend eternity in hell for temporal sins?
Some folks think that it’s unfair for God to exact eternal punishment for transitory sins. As finite and mortal beings, we don’t have all the facts. We have no knowledge of things eternal. Only God can see perfectly and understand such issues. His word provides us with this simple fact: sin results in death. (Rom. 6:23)
On one side, God loved you and me so much that He gave His only Son to be the sacrifice for our sins. He paid the price for the wrong we do. On the opposite side exists an equally strong condition: a certain expectation of judgment. It is a terrifying thing to fall into the hands of the Living God. (Heb 10:26-31)