1. When Britta and Troy dated on Community.
2. Hayley getting back with Dylan and then getting pregnant on Modern Family.
3. Michael coming back after he had presumably died on Jane the Virgin.
4. Spencer having an evil twin at the end of Pretty Little Liars.
5. Mr. Turner getting into a motorcycle accident on Boy Meets World.
6. Lily and Rufus meeting their son on Gossip Girl.
7. Rachel and Joey’s romance on Friends.
8. Ben's whole existence on Friends.
9. Quinn getting in a car accident and being in a wheelchair on Glee.
10. When Blaine and Karofsky dated on Glee.
11. Eleven finding her siblings on Stranger Things.
12. Archie dating his teacher Miss Grundy in the first season of Riverdale.
13. The whole Olivia kidnapping storyline on Scandal.
14. When Finn kissed Emma soon before her wedding to Mr. Schue on Glee.
15. Randy and Donna's relationship on That '70s Show.
16. Cameron being in love with House on House.
17. Bryce's redemption arc on 13 Reasons Why.
18. Debra getting over her stepbrother being a serial killer and realizing she had romantic feelings for him on Dexter.
19. When Omar cheated on Ander with his sister's boyfriend on Elite.
20. Pam and Jim having marital problems in the final season of The Office.
21. Emma and Spinner getting married on Degrassi: The Next Generation.
22. Leo cheating on Grace on Will and Grace.
23. When Reagan was a replacement for Jess on New Girl.
24. Ian and Lip getting DNA tests done on Shameless and finding out Ian is not Frank’s son, but the son of one of Frank’s brothers.
25. When Emma's stepdad, Mr. Simpson, cheated on her mom on Degrassi: The Next Generation.
26. When Schmidt cheated on Cece on New Girl.
27. Luke discovering he had a daughter on Gilmore Girls.
28. Landry killing a guy on Friday Night Lights.
29. The tickling-videos storyline on Riverdale.
30. Izzie having a brain tumor that resulted in her having sex with her dead ghost boyfriend on Grey's Anatomy.
31. Caleb and Spencer's relationship on Pretty Little Liars.
32. Annie’s cousin staying with her family on 90210 and ruining Annie's social life for no reason.
33. The whole last season of Once Upon a Time.
34. Tom finding out he had a daughter before he and Lynette were together on Desperate Housewives.
35. On Glee, when Rachel gave up her dream Broadway role in Funny Girl to star in that really bad TV show that got canceled.
36. The whole high school musical storyline in Season 1 of The Politician.
37. Frank being revealed as the child of Sam and Hannah's incestuous relationship on How to Get Away With Murder.
38. And Ted going back to Robin on the series finale of How I Met Your Mother.
Note: Some submissions have been edited for length and/or clarity.