I love this thread!!! And I love (most) dysfunctional couples!
1. Jonathan & Victoria. Absolutely no doubt about it!!
2. Lori & Bolo
3. Nathan & Jennifer
4. Lake & Michelle
5. Tara & Wil
Special Mentions: Alison & Donny and Preston & Jennifer probably could've been on this list if they lasted longer, especially the former. Brent & Caite and Carol & Brandy both deserve mentions. Colin & Christie were dysfunctional, but I can't stand them.
MoJo deserves a big mention and are #6 on my list! MoJo Thailand Meltdowns were some of the most awesome scenes ever!!!
Of course, if Flo & Zach were a couple, they would be #2 on the list. But as they were not dating, I didn't include them in my calculations.