The problem of hell is a version of the problem of evil.

It might be worth reading this: https://plato.stanford.edu/entries/evil/

If it's too technical, you might try the Wikipedia article, here are a few excerpts:

The logical argument from evil is as follows:

P1. If an omnipotent, omnibenevolent and omniscient god exists, then evil does not.

P2. There is evil in the world.

C1. Therefore, an omnipotent, omnibenevolent and omniscient god does not exist.

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If God lacks any one of these qualities – omniscience, omnipotence, or omnibenevolence – then the logical problem of evil can be resolved. Process theology and open theism are modern positions that limit God's omnipotence or omniscience (as defined in traditional theology) based on free will in others.

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A version [of the evidential problem of evil] by William L. Rowe:

1. There exist instances of intense suffering which an omnipotent, omniscient being could have prevented without thereby losing some greater good or permitting some evil equally bad or worse.
2. An omniscient, wholly good being would prevent the occurrence of any intense suffering it could, unless it could not do so without thereby losing some greater good or permitting some evil equally bad or worse.
3. (Therefore) There does not exist an omnipotent, omniscient, wholly good being.

Another by Paul Draper:

1. Gratuitous evils exist.
2. The hypothesis of indifference, i.e., that if there are supernatural beings they are indifferent to gratuitous evils, is a better explanation for (1) than theism.
3. Therefore, evidence prefers that no god, as commonly understood by theists, exists.

It should also be mentioned that most lay people's concept of hell is radically different than the hell as described in various scriptures. I would be wary of any singular depiction of hell even within a religion, as scripture often has contradicting things to say about hell (with multiple plausible interpretations), and contemporary beliefs about hell are more informed by popular culture than scripture anyway.

Again, I direct to Wikipedia for the different depictions of hell: https://en.wikipedia.org/wiki/Hell

I am an atheist and this is still pretty easy to answer:

Your parents probably love you unconditionally, too, that doesn't mean they didn't punish you when you misbehaved growing up.

I'm not quite sure where your interpretation of heaven and hell is coming from, but the Christian Bible doesn't describe them in any way that what you said makes sense.

You're trying to put emotions into the afterlife and describe nature as a 'he'. Unless you know of someone going to the other side and reporting back, it's all just speculation.

Because, without an instrument to incite fear, religion would be useless for the upper class.

Where are you getting this interpretation of heaven and hell from? I’ve never heard anything like it.

I’m a Thelemite, and in our tradition, duality is an illusion. Good and evil, suffering and pleasure, life and death—we see these things as two sides of the same coin, and reaching an enlightened perspective through meditation can show you that they have never been opposites at all, rather a continuum.

What you’ve described is basically a formula of “Heaven is LSD, Hell is heroin” and that doesn’t match up with anything I have experienced, read, or heard before. Without explaining your position more, I don’t really know how to discuss it.

Here's another one: if evil didn't exist, we wouldn't be able to appreciate good. Does that mean the devil is required for us to truly appreciate god? Shouldn't we therefore be thankful to Satan?

It’s a well researched question, the solution is that an all loving god does not exist.

I can't say for sure what religion you're talking about, so I don't know much of the religious context for this definition of heaven and hell. My issue with this definition is emotions are so much more complex than "happy is good, sad is bad". A lot of people who have dealt with depression (including myself) will tell you that it's far worse to feel nothing at all. I'd much rather feel the sorrow or hate, and have help from God to work through those feelings.

I find the Christian (specifically protestant Arminian, and yes that is my religion) answer to this question much better. Basically, hell is the other option to heaven. Heaven is where God is fully present, so there must be somewhere else for those who reject God to go. That place must be fully apart from God, otherwise he would not be honoring their decision, and so he would not be all loving.

For me he'll is a place of our own making. Like, heaven is a state of being we grow into. Like dieting and exercise changes us for the better, commandments are there just to help us grow into a better being that is heavenly (more and more like God). Hell is the state of missing out on that eternal progression. Which means is is always an option available to us, and it doesn't come from God but ourselves.

The answer is well rehearsed: god works in mysterious ways. If we understood how god thinks, we would be god, but alas, we are not.

There's no scriptural references I know of off the top of my head about increasing and decreasing feelings. But if you have some, please share.

Because God is all perfect, so God is all loving, but also perfectly Just. A loving God would set the reward to be to bring His children to him, but imperfect children cannot be in His presence, as God is also perfectly Just, so sin needs to be punished. Because sin transgresses God greatly, it cannot be erased by doing the right thing. We always have to do the right thing regardless. You cannot make a fine for running a red light go away because you stopped at the next three red lights. You need to pay with something above the road- driving. So the payment for our sin is above this world.

God is all loving, so 2000 years ago, he became incarnate as a man and lived as one of us. He ended up suffering, dying and He was buried. He lived a perfect life - the life we should have lived. Yet he died the death we deserved, and descended into Hell for three days. A perfect sacrifice was made. Now, all heaven requires is simply renouncing our allegiance to sin and turning it back to God.