Farrah and Simon squabbled quite a bit when they appeared together on Teen Mom OG and ultimately wound up as exes. And the bickering didn't exactly continue when he blindsided his former girlfriend on the beach (because no in-depth convo actually occurred and he was promptly cut from the series).

But looking back, what disagreement between Farrah and Simon stands out among the rest?

"I think over the years on Teen Mom, the biggest disagreement was about an engagement ring that we had a little situation over," Sophia's mama revealed to MTV News. "That stood out because that’s a life-changing and loving memento, and that turned into an ugly situation and about money. That’s disgusting, and he’s disgusting, so that was the biggest situation."

Farrah is referring to a part of her life from 2016, but the moment was not featured on TMOG. Some context: The entrepreneur was in the Bahamas with her mini-me (celebrating the little lady's birthday), and the duo found themselves in a jewelry store. Sophia encouraged her mama to try on rings and pick something out to signify her bond with Simon. Farrah gave Simon a call to ask if he was okay with this idea and to make sure he was involved, and he even spoke with the owner of the business about how to customize it. She took care of the purchase -- and he never paid her back.

The aftermath of the shopping story was featured on TMOG -- and, as the video below shows, reliving the situation with Simon and Dr. Jenn during a therapy session was emotional and painful.

No closure was exactly reached between the two in Malibu, but what do you think the future holds for Farrah and Simon? Give us your take and be sure to keep watching Ex on the Beach with Farrah (sans Simon) on Thursdays at 8/7c.