Heroes save people, even enemies. What's more, if a hero saves a rival or villain enough times, you'd expect them to change their attitude towards the hero into one of at least grudging respect or having honor dictate that they "owe them one".
You'd be wrong.
Heroes don't always get gratitude, recognition, or even a basic "thank you" for their efforts, and sometimes, any thanks are patently insincere. Rivals and enemies in particular tend to treat these saves with the same gratitude for the air they breathe (read, none). And that's if they aren't actively angry at being put through the ignominy of being saved by those filthy freaks, they'll usually betray such mercy at the first opportunity. Ungrateful Bastards. Nothing says better that someone is an irredeemable scumbag, more than treating the (often unwarranted) mercy and kindness as nothing or even worse as a weakness to be exploited.
This is true even if it's a forced Enemy Mine situation, and he never even acknowledges the service rendered or is grateful, much less gets Character Development or a change in their relationship to reset. This might be done either to show how utterly evil (or at least callous) the enemy is, and avoid having the show's formula change with the Big Bad growing unable to kill or hate someone who has saved them so often.
See also Never Accepted in His Hometown for cases where the hero's own people act like this, Ungrateful Townsfolk for people who carry it to the point of outright hostility or betrayal, What Have You Done for Me Lately? for people being particularly blunt about their lack of gratitude, and Zero-Approval Gambit for situations where the hero wants to be disliked.
- Anime and Manga
- Comic Books
- Fan Works
- Live-Action TV
- Video Games
- Western Animation