The GTA5 torture scene with Trevor and the car battery, pliers, etc. was difficult to participate in. If I recall correctly, he at least didn't get anything useful out of him, which would've implied that the ends justified the means.
In the game, you are forced to participate in torture of a guy for absolutely no reason. You have to select torture methods, then manipulate the controls to adequately complete the mission.
In another mission, as another character, you're forced to perform an assassination for a government organization. As the scene unfolds, it becomes clear that they have no idea what they're doing, and they're just reacting immediately to low-quality intel.