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 they have 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 or Bitches. Nothing says better that someone is an irredeemable, honourless scumbag more than treating the (often unwarranted) mercy and kindness as nothing or even worse as a weakness to be exploited.
There are odd times nevertheless, where the lack of gratitude may be explained or even more surprisingly justified by a number of reasons that make the subject less of a bastard and more of a rational fed-up individual. For instance, who can blame characters for being "ungrateful" if they were put in danger by the good intentions of the Heroic Wannabe, and whose "rescue" possibly led to their injury or destruction of their property? This becomes more understandable if the "hero" has previously antagonized or outright harmed the character, or provides or even forces Unwanted Assistance upon them. A Death Seeker getting saved from certain death has little reason to be happy in the short term since the cause for seeking death remains unchanged, but they will come across as less scummy and indignant compared to instances like the Dirty Coward who feigns indignation at being saved to try and salvage a facade of bravery.
This is true even if it's a forced Enemy Mine situation, and they never even acknowledge the service rendered or are 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 or The Farmer and the Viper 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.
Contrast Grudging "Thank You", Because You Were Nice to Me, and definitely I Owe You My Life, where gratitude is given or shown in little to no uncertain terms and in the latter cases, results in the favor being actively repaid as often as not if only to even the score. Probably not related to the inglourious kind. See also Entitled Bastard who not only doesn't thank the heroes, but also expects them to save them anyways.
Examples
- Anime & Manga
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- Live-Action TV
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- Western Animation
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