1. When Ben had sex with his wife while his girlfriend was hidden in the closet in He's Just Not That Into You.
2. Erin almost killing herself in What Women Want.
3. When Vivian was almost sexually assaulted in Pretty Woman.
4. Karen discovering her husband's affair in Love Actually.
5. When Tim goes back in time to say goodbye to his dead dad in About Time.
6. Gareth's sudden death in Four Weddings and a Funeral.
7. When Olive's fake date forced himself on her in Easy A.
8. Amy's dad dying of an overdose in Trainwreck.
9. When Jenna realised she ruined her chances with Matty in 13 Going on 30.
10. The timeline where Helen dies in Sliding Doors.
11. When it was revealed that Meryl cheated on Paul in Did You Hear About the Morgans?
12. Lara Jean dealing with her mum's death in To All the Boys I've Loved Before.
13. When Emma died suddenly at the end of One Day.
14. When Matt was raped in 40 Days and 40 Nights.
15. Elle being propositioned by her professor in Legally Blonde.
16. When Nick's mum tells Rachel she's not good enough for him in Crazy Rich Asians.
17. Rosie's miscarriage in What to Expect When You're Expecting.
18. And finally, the strange ending of 50 First Dates.
Submissions have been edited for length and clarity.