Basic Trope: Something bad needs to have happened to prevent something worse happening.
- Straight: Alice gets shot in the shoulder and almost dies. She's fine, but Bob feels bad because he was the one who led her on the adventure that led up to her being shot, so he goes back in time and prevents Alice from getting shot by talking her into buying a snack from the vending machine, but then it turns out that if Charles hadn't shot Alice at that particular moment, he would never have been arrested by the coincidentally-nearby police, which would've led to him succeeding in killing Alice later on and still being at large.
- Exaggerated: If Charles hadn't shot Alice, he would never have been arrested, which would lead to him blowing up the world.
- Downplayed: Bob goes back in time to stop Alice from stubbing her toe, which leads to her skinning her knee instead.
- Justified: Unfortunately, this is how most safety regulations came into being.
- Inverted: Charles goes back in time to shoot Alice (not to prevent anything, he's just psycho), however, it turns out that shooting Alice leads to his arrest, and she survives anyway.
- Subverted: Bob goes back in time again and makes it so that Alice avoids getting shot by Bob but the police see him try to shoot Alice and arrest him, thereby getting Charles arrested and having Alice survive uninjured.
- Double Subverted:
- Parodied: Bob goes back in time to stop Alice from dropping her ice cream, which somehow leads to the Nazis winning World War II.
- Zigzagged: If Charles hadn't shot Alice then, he would still be at large, but he still wouldn't have succeeded in killing her, however, he would have killed her mother, but that would have prevented Bob from breaking his leg, however, it would've also prevented Alice's sister Diane from being born.
- Averted: Bob doesn't even consider going back in time to prevent Alice from being shot; he's just happy she's alive.
- Enforced: The writers wanted to add An Aesop about how failure is sometimes OK.
- Lampshaded: "Seriously?! Does the universe not want things to go Alice's way?"
- Invoked: Charles talks Bob into going back in time so that he can succeed in killing Alice and getting away.
- Exploited:
- Defied: Alice talks Bob out of going back in time to save her.Alice: "Bob, it's not your fault. He's just evil, but he's in prison now, I'm fine, and if you go back in time and prevent this, who knows what would happen?!"
- Discussed: "What do I do now, do I go back and time and prevent Alice from being shot? No, no, no, bad idea, something even worse might happen."
- Conversed: "I've never seen any movie or TV show where going back in time to prevent something bad happening doesn't turn out to be a bad idea."
- Implied:
- Deconstructed:
- Reconstructed:
- Played for Laughs:
- Played for Drama: Bob feels like a failure because nothing he does ends up being right.
Back to Necessary Fail.
