Why not start with a biggie!
The more I think about the idea of Hell, the more silly it sounds. Most definitions of Hell involve the idea of eternal punishment for sins, or a place of eternal suffering. In fact, I'd go as far as to say that if a definition of Hell doesn't include the idea of eternal suffering, then it's not a definition of Hell, but of something else. Whether this suffering is direct or indirect, physical, psychological or spiritual is not the issue here. Suffering is suffering, whatever form it takes.
Humans are finite creatures, who live for a finite period of time. Within this period of time, they can carry out a finite number of actions, each of which with finite consequences. Consequently, a single person can commit only a finite amount of sin.
If justice entails meting an amount of sin with an appropriate amount of punishment (notice the "if" - we can quibble about this idea of justice later), and if God is perfectly just, then punishment in Hell has to equate to punishment for an infinite amount of sin.
If no man can commit an infinite amount of sin, and some humans end up in Hell, then we have a contradiction. One of our premises above is wrong. Either a) God is not perfectly just; or b) Hell does not involve eternal suffering; or c) a single, finite, human being can in fact commit an infinite amount of sin; or d) no human will ever end up in Hell.
Which is it to be?