Japan had a human experimentation unit that they disguised as a regular biological research facility in WW2. They refered to the people they experimented on (including men, women, children and infants born out of forced impregnation during 'research') as logs. They did horrible stuff for shits and giggles like attaching someone's limb to the oppos......
My fave non romance trope is a character being stuck in a time loop and slowly losing their sanity. Romance wise, the scene where one character sleeps on anothers shoulder in a train is just on another level.
Disturbing facts