We asked members of the BuzzFeed Community to tell us which TV couples should've ended up together but didn't. Here's what they said:
1. Castiel and Dean on Supernatural

2. Rachel Green and Joey Tribbiani on Friends

3. Lexa and Clarke Griffin on The 100

4. Tina Cohen-Chang and Mike Chang on Glee

5. Barney Stinson and Robin Scherbatsky on How I Met Your Mother

6. Buffy Summers and Angel on Buffy the Vampire Slayer

7. Arizona Robbins and Callie Torres on Grey's Anatomy

8. Penelope Garcia and Derek Morgan on Criminal Minds

9. Jane Villanueva and Michael Cordero on Jane the Virgin

10. Kara Danvers and Lena Luthor on Supergirl

11. Rory Gilmore and Jess Mariano on Gilmore Girls

12. Jackson Avery and April Kepner on Grey's Anatomy

13. Bellamy Blake and Clarke Griffin on The 100

14. Jennifer "JJ" Jareau and Spencer Reid on Criminal Minds

15. Emily Fields and Maya St. Germain on Pretty Little Liars

16. Andy Bailey and Haley Dunphy on Modern Family

17. And finally, Alex Karev and Jo Wilson on Grey's Anatomy

Note: Some responses have been edited for length and/or clarity.