When the villain with no redeemable qualities shows a rare moment of weakness/regret
Conquest - Invincible: Before killing Mark, he admits to him that he is incredibly lonely, that all the other Viltrumites fear and laments the fact that he doesn’t have a name, only a purpose. He says he is capable of more but no one knows it and sometimes feels like crying but doesn’t bother because no-one in the entire universe would care.
The Lich - Adventure Time: Whilst confronting Golb (his creator) he talks about how even after fulfilling his purpose of ending all life in the universe, he didn’t feel any satisfaction and that he has now lost all purpose in existing.