Hell or annihilation

[Bohandas]

No, not at hellish levels.
People endure mundane sufference like squallor, poverty, even hunger and moderate levels of violence.
People flee en masse when things like gruesome public executions and genocide happens, and Hell is that multiplied for a thousand.

Honestly D&D's hell, as described in the books, doesn't seem all that extreme. Their punishments fall short of the breaking wheel and crucifixion, the intrusiveness of their security falls short of the TSA, and most of the people in charge worked their way up from the bottom legitimately (with the notable exceptions of Asmodeus and the Lord of Malebolge), or at least what passes for legitimately in hell.