The most horrendous conditions in human life have been created by other humans. We maim, torture, and humiliate individuals to penalize them for their actions with callous indifference to their suffering, or in some cases, with the intent to cause as much pain as possible.
The purpose of punishment is arguable: some believe human beings punish criminals to reduce crime through deterrence or maybe to rehabilitate offenders. Some think it's to rid criminals from society in efforts to protect the public, but undoubtedly there have been punishments intended to cause pain to the condemned.
There are cases, both ancient and modern, of men and women burned, drowned, and torn apart all with the intention of punishing them for their real and, in some cases, suspected crimes in the most painful manner.