Some people imagine boiling in oil, others suffocating.
In my personal vision of hell, I'm eternally on rappel, trying to retrieve stuck ropes. To prevent hell on earth, step one is to avoid stuck ropes in the first place. Start by minimizing rope friction both at the anchor and against the rock. Ledges are nice for standing on and setting an anchor, but the friction of a rope running across a ledge can make the rap line hard to retrieve. If you're rapping from a ledge, set your anchor high to reduce friction.