Hell and Paradise is nothing but our deeds -in their real faces.
On the Day when every person will be confronted with all the good he has done, and all the evil he has done, he will wish that there were a great distance between him and his evil. ... (3:30)
So whosoever does good equal to the weight of an atom (or a small ant), shall see it. And whosoever does evil equal to the weight of an atom (or a small ant), shall see it. (99:7-8)
As the Aya says, hell and paradise, and all those suffers and enjoyments described in Quran, are just the real face of our own deeds.
The following Aya makes it clear:
On the Day when that (Al-Kanz: money, gold and silver, etc., the Zakat of which has not been paid) will be heated in the Fire of Hell and with it will be branded their foreheads, their flanks, and their backs, (and it will be said unto them): "This is the treasure which you hoarded for yourselves. Now taste of what you used to hoard." (9:35)
Yes. The fire, the hot metals and stones in hell, are not only equals or equivalents for our sins; They are exactly the sins itself. The same for paradise. For example, I steal some chocolates from someone's pocket. In this world, I eat the chocolates and it has a delicious taste to me. But when I die and then get back to God, I'll see the real face inside my action, and I'll realize what an evil my deed was, and this tortures me. Now it tastes so terrible, as Quran describes the hell and what is ate there.
This analogy might help: Imagine you are a lover of Physics science. Some day, you happen to be traveling a long way by train, and a man is sitting aside you. At end of the journey, you notice the man was the biggest physicist of all time, but it's too late and you no longer have access to him. If you knew who he was, you'd learn a lot from him, about his experience, his field, and so. Now that your eyes are open, and you see that you missed the chance, you are upset. You tell yourself "Why didn't I notice" and you feel a burn in fire of your own negligence. Hell is the same. You see your sins, and it's enough to burn in fire. Both mentally and physically.
Summary: God doesn't need to vent his anger on some poor people, neither doesn't need people to worship him. Hell and Paradise is nothing but our deeds as seen through an open, awake eye.