This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / A Fistful of Dynamite
If you were in Juan's place when he rode that carriage in the beginning of the film, you'd be pretty hurt by the other people talking about you like you weren't there, like you weren't human.
The discovery that Juan's entire band of outlaws, including all of his sons, have been brutally massacred. And of course John's death.
The execution scene. John's moment of horror, too, once he finds that Dr. Villega is a traitor.
Juan begins the story only interested in riches and getting that one big score. Later in the story after the death of his family, he finds himself with a bag of valuables worth a small fortune. They may as well be made from tin for all Juan cares. John's silent acknowledgement of the situation is equally heartbreaking.
The looks shared between Juan and John while hiding out in the cargo carriage of a train. John catches Juan wiping away his tears, and tries to look away because he knows that it'll make Juan ashamed of himself and just feel worse.
Heck, is there another film where you can feel this way about the traitor? Nolan and Dr. Villega alike. Of course the fact that both became traitors only due to torture helps. And while not on a Tear Jerker level, you even feel sorry for Gunther Reza after the bridge explosion (of course, this happens before he's crossed Moral Event Horizon).