I got arrested about eleven years ago on my way home from work for driving on expired plates and having a warrant out on me for not showing up in traffic court. I got pulled over and they took me in. I slept in a local police station cell on a sheet-metal bed with no pillow and a crappy blanket, which I used as a pillow, so I froze. The next morning they took me to the county courthouse and locked me up in holding cell with about twenty other people who had been arrested the night before. Many of them were still drunk. Many of them stunk, bad. The toilet was a hole in the floor in the corner, where a couple of the drunk guys puked. The door to the cell was plexiglass with a small gap at the bottom. Ventilation was terrible and it smelled so bad. I stood in that cell for six hours (only place to sit was the floor and that wasn't going to happen). Eventually it was my turn to go before the bond judge. When he saw I'd never been arrested before he rolled his eyes and told me to go home. I took a bus back to my car, ate a hotdog, and went directly back to work.
From that 19 hour experience I can say that prison is most certainly torture, but a psychologocal kind. You feel very low, worthless. I knew after that, but only in a hypothetical sense, of course, that if I was ever sentenced to a prison term I'd kill myself. I can't see why anyone would choose life in prison over the death penalty. I'd much rather get strapped in for the big sleep than live out my days in a hell-hole like a prison. And I can see why so many released inmates come out more screwed up than when they went in.