Tempting Fate/Fan Works

"Vegeta: They've broken my body... I've failed in my mission to get the Dragon Balls... I've even lost my tail... But at least, it can't get any worse from here... Vegeta: W-What? Vegeta: NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOooooooooo!"
 * Episode 10 of Dragonball Z Abridged ends with this following gem:
 * Vegeeeetaaa... Vegeeeetaaa...

"Goku: He's getting huge. That means he'll only be stronger. That means he won't be as fa--OH GOD HE'S STILL AS FAST!"
 * That happened more than once in episode 10...

"Krillin: We won't ever have to see him again! (Vegeta falls next to Krillin) Krillin: ... alive again. I meant we won't ever have to see him alive again! (naturally, Vegeta is alive)"
 * Also from episode 10 of DBZA:

"Tristan: I sure hope we don't encounter any more intrusive subplots. Jean Claude Magnum: Did somebody say "intrusive subplot"? Tristan: Oh, son of a bitch!"
 * In Episode 18, Vegeta brags to Goku that besides Freeza he's the most powerful being on the planet. Cue the Ginyu Force showing up.
 * "That's right. I'm your white mage. And nobody fucks with the white mage." Three guesses as to what happens immediately afterwards.
 * The frigate officer in the Warhammer 40K fan-film Damnatus -- "We have never arrived too late before."
 * In Smashtasm there is a running gag wherein a character will say: "There's no way that ((insert bad thing)), especially not right now! Super64, being Genre Savvy, tries to invoke this trope when he gets captured, saying:
 * There's no way I could get out of here. Especially not right now."
 * The Lord of the Rings metafic epic The Official Fanfiction University of Middle Earth tackles this in an early chapter, when the heroine spends a day with everything going wrong determinedly resisting the temptation to demand what else could go wrong ("for as everyone know, that is an invitation to get a demonstration of just what else can go wrong. The gods/God/evil forces/whatever you believed in were nothing if not equipped with a sense of irony. It's a vital God-quality, that."), until one thing too many does and she lets it slip. She then yells out that she didn't mean it... to no avail.
 * Yu-Gi-Oh!: The Abridged Series utilizes this for humor on a few occasions:
 * On the way to the blimp:
 * On the way to the blimp:

"Doctor: I'm glad I have such a long and villain-free life ahead of me. Melvin: Hi there. Could I get a hug? Dr. Feelgood: A hug? Sure, I don't see why not. (the sounds of chainsaw revving can be heard) Oh my god, it burns, it burns!"
 * On the blimp:

"Harry: No way this year anyone's gonna die!"
 * From the very first song of A Very Potter Musical:

"Azura: (Mario lands on safe ground) I'm alive! (Mario dies) Azura: I'm dead!"
 * In Kyon: Big Damn Hero Kyon named his PDA Skynet. It's made from some of Asakura Ryoko's data, so it's capable of learning.
 * Koizumi muses that he's the most normal among the extended SOS Brigade. He soon gets an upgrade to his ESPer powers.
 * This Sonic fanart.
 * In this Let's Play by Azureblade 49, a choice quote that goes well with this trope:

"Dornkirk: You can't destroy it you silly girl! It's protected by causality itself! There isn't a force in the world that can possibly destroy it. (Van smashes through) Dornkirk: ... except for that."
 * In the 26th video of Ultra J Man's Let's Play I Wanna Be the Guy, he is still angry, and he declares Guess what happens.
 * Profound Moments in Left 4 Dead 2: "I'm gonna do this entire campaign with 1 HP and beat the shit out of everything with a first aid kit."
 * The second part of the last episode of Vision of Escaflowne Abridged.

"Inara: They seem to be expecting an auditor. The Doctor: Good. No one will get too fussed when we go about asking nosy questions then. Inara: As long as the real auditors don't show up, we should be alright. The Doctor: *winces* Oh, did you have to say that? Now they're bound to turn up. I swear, everyone has to go and jinx it all, saying things like 'It can't possibly get any worse' or 'Ooh, it's unsinkable!'"
 * Upon getting 8 red coins in a difficult Super Mario Sunshine level, Chuggaaconroy jokes "Yay. Now watch me die on the way to that." And we do. (around 8:55)
 * During the outtakes from the third Rival battle: "What the heck was I worried about, it's a freaking Rattata." "WHAT?! WHAT?! WHAT?!"
 * In Awesomeness of the Ocarina this trope is inverted and discussed. "Even though Navi tempted fate with the dreaded "It can't get any worse" stock phrase, things actually got better. Link noticed this, but he didn't want to push his luck."
 * Subverted in episode 45 of Pretty Cure Heavy Metal. After taking a single whiff of a cigarette, Shugo says she doesn't want to get addicted. Guess what? She's remained smoke-free ever since.
 * Lampshaded in Harry Potter and the Methods of Rationality during the arc. Dumbledore declared himself invincible and an   asks in astonished horror if he really just said that. Her commander says that he can get away with it since not even fate takes Dumbledore seriously anymore.
 * In A Hero, the second chapter has Dalek Sec watching Homura battle Walpurgisnacht from afar, and concluding that the Witch isn't looking his way, and wouldn't attack him. Fortunately, Sec's Genre Savvy enough to realize what he just did, which gives him just enough time to learn that a horde of familiars are heading his way.
 * This is referenced in The Man With No Name while some characters are infiltrating the enemy stronghold..

""Now, this is your operation," I said, raising a finger. "I'm here as backup only. If these two are like the critter in the jewelry store, you should be able to handle them by yourself. I'll be hanging back, and I'll only step in if you get in trouble." I put a hand on her shoulder.  "This should be easy." It would take less than ten minutes for me to regret jinxing us that way."
 * In the Katawa Shoujo fic Lilly Epilogue (Good End): Family Matters, Hisao narrates that "Considering that just one year ago I probably felt like the most pathetic sap on the planet, things are definitely looking up. Everything just feels right with the world." In the next scene, he finds out that his girlfriend Lilly's parents are coming to visit, prompting him to think "Oh fuck".
 * Turnabout Storm:
 * Phoenix comments on how the prosecutors in his world are almost always stuck-up, smug and arrogant. Twilight assures him that nopony in Equestria is like that... Cue Trixie making entrance... loudly.
 * What is one of Phoenix's last lines before being summoned to the Sugar Bowl that is Equestria? "Unfortunately, sunshine and smiles don't pay the bills."
 * Doug Sangnoir of Drunkard's Walk, who is usually Genre Savvy to dangerous levels, does this without thinking about it at the start of Sailor Moon's third mission in chapter 2 of Drunkard's Walk S: Heart of Steel: