Any of the slave labor camps:
Wano's Udon prison - You mine and move stone all day for the equivalent of cornmeal until you drop dead.
WG's Tequila Wolf - Harsh weather, regular whippings, constantly on the move to keep up with construction.
Impel Down - Crimson Hell where sharp spikes are driven through your body and you're left to bleed all over. Blazing Hell where your bare feet burn as you perform hard labor and get tossed into a boiling pit if you fail.
Sugar's Toys - You have been forgotten by the world, you have a weak metal or wooden body that can't sense, your body moves against its own will even if you have long given up.