Thank god they dropped that whole Landry-killing-someone storyline on Friday Night Lights.
1. When Rufus and Lily's son on Gossip Girl was completely erased and never mentioned again...likely because his existence made the Dan-Serena relationship feel a little incestuous:

The CW
"I’m not sure if he disappeared because people hated it, but he definitely never showed up again. ... I will add that I hated it. I mean, it didn’t make Dan and Serena related by any means, but when you share a sibling it’s more than a bit fucked up."
2. And when there was an entire convoluted storyline about Chuck trying to figure out who his mother was that ended with him wondering if his Uncle Jack was his father... Then it was never mentioned again:

The CW
"The whole storyline about Jack Bass being Chuck's real father... Still not sure who his mother is supposed to be."
—jo97
3. When the reboot of Will and Grace decided the events of the last season — aka Will and Grace both having kids — were just a dream:
NBC
4. The whole Lily plotline on Once Upon a Time:
ABC
"Once Upon a Time dropped many plotlines. They dropped the 'dark Savior' storyline with Lily and Maleficent, which they'd spent all season building up to."
5. When the unpopular character Seven was introduced on Married With Children, then disappeared as if he'd never existed...except for a quick shot of him listed as missing on the back of a milk carton:
Fox
"My fave was Married With Children. They had a new addition to the house. He was 10, and his name was Seven. Ten episodes later, he was gone and never mentioned again (except that one time his face appeared on a milk carton)."
7. When the Futurama movie Bender's Big Score reversed the events of episode "Jurassic Bark," which was — while loved — often cited as one of the most depressing episodes of the series.
Fox / 20th Century Fox Home Entertainment
"It wasn't because the original was bad or hated, but I believe Futurama did this with Seymour the dog. The series showed him waiting and dying of old age, waiting for Fry every day. When the series was rebooted into movies, they showed Seymour being with a time-traveling Fry. ... I think they just wanted to soften it a bit with the movie."
—zemt
8. When Landry killed someone on Friday Night Lights and then the storyline was completely dropped after it was received poorly:
NBC
"When Landry kills that guy and then his police officer father helps cover it up. I get that they called it 'self-defense,' but the writers really wrote themselves into a corner with that one. My favorite was Landry just getting a new car, and no mention why he needed a new one."
9. The entire Dean/Amelia relationship on Supernatural:
The CW
"Supernatural Season 8 had a storyline going in the flashbacks about what Sam was doing when Dean was in Purgatory, where he accidentally ran over a dog and started a relationship with a woman called Amelia. Fans hated this storyline so much that when the season returned from the winter hiatus, it was never revisited or resolved. Even Jared Padalecki hated what it meant for Sam. It didn’t help that it was a very lazy rehash of Dean’s storyline between seasons 5 and 6, as Dean’s yearning for a normal life as well as the relationship with Lisa and her son Ben were already well established, and the increasing difficulty in handling the family man and Hunter lifestyles was shown in Season 6 to a tragic logical conclusion."
10. Patrick Gordon's storyline on Downton Abbey:
PBS
"There was a storyline on Downton Abbey where a soldier with a badly burned face claims to be the real heir to the estate who had supposedly died aboard the Titanic in the first episode, and Edith starts falling in love with him. It was a terrible storyline, and I can’t remember how it resolved, but the character was quickly dispatched and never mentioned again."
11. When unpopular character Mark Brendanawicz got another job in Pawnee on Parks and Recreation, but was never seen again:
Mitchell Haaseth / NBC / Courtesy Everett Collection
"He leaves the parks department for another job that is still in Pawnee, but is never heard from again. They are constantly having fairs and town meetings, and he never even shows up to say hi. I’m not even mad about it though; I thought his character sucked, and they tried to make him like Jim from The Office, but it didn’t land. The show got way better when they added Chris and Ben and got rid of Mark."
12. When a woman claiming to be Anne Frank arrived at the asylum in American Horror Story: Asylum, and her storyline (of how she knew Arden) was never resolved:
Byron Cohen/FX Networks / courtesy Everett Collection
"AHS is notorious for starting a storyline with no clue as to where it's going and then dropping it halfway or rushing it through with a clumsy resolve. What sticks out to me is Season 2 (Asylum) and the Anne Frank storyline."
—kmrp
13. When Jackson became selectman on Gilmore Girls in a rather underwhelming plotline, and then the next season Taylor was back to being selectman as if the election had never happened:
The WB
"When Jackson becomes town selectman and they follow it up for a while, and then one day Taylor is back to having that role, and they never explain what happened with Jackson or mention it again."
14. And when Jason and Lorelai broke up because he was suing Lorelai's father...which was then never mentioned again:
The WB
"They break up, but you never hear the results or repercussions of the lawsuit."
15. When new characters Marley, Kitty, Jake, and Ryder were introduced on Glee and took over the main cast, and then all got demoted or disappeared in the final season:
Mike Yarish / Fox / Courtesy: Everett Collection
"It's so hated amongst Glee fans that they acted like they didn’t exist the next season, and then the next time they were ever seen was in the finale."
16. When Phoebe discovered her mom's friend was her birth mom on Friends, and then the character disappeared:
NBC
"One of my biggest pet peeves is in Friends. Although it’s my favorite show and I watch it every day, when they introduced Phoebe’s ‘birth mom’ I cringed and still cringe to this day. That storyline was absolutely pointless. We meet her like, three times at the end of Season 3 and beginning of 4, and [then] she’s never mentioned again after the birth of the triplets. It winds me up every single time because it’s just so ridiculous."
17. And finally, when Samantha slept with Charlotte's brother on Sex and the City, leading to some problematic slut-shaming...then the brother literally disappeared from existence:
HBO
"Charlotte had a brother for one episode of SATC. Samantha slept with him and then he was never heard from again."
Now for another question — what bad or stupid TV plotline do you *wish* was erased? Let us know in the comments!
Note: Submissions have been edited for length and/or clarity.