If we had made a "Least Likely To Beef" list heading into 2015, YG and DJ Mustard probably would have been at the top. Yet, here we are, with the New Year creeping up on us, and the two West Coast hitmakers are on edge.

On Monday, personal and business issues spilled over into the public forum, when the rapper and producer exchanged a number of shots at one another on social media. Mustard claimed that he hadn't been paid for his work on YG's album, My Krazy Life, while YG said that he never got paid for the vocal drop, "Mustard on the beat, h--," which appears at the beginning of Mustard's beats.

It's a pretty startling and unfortunate shift, and there are plenty of reasons we hope they repair their working and personal relationship. Here are a few.

They collaborated heavily on one of the year's best rap albums -- and we want more where that came from

Mustard produced a handful of beats on My Krazy Life, including "Bicken Back Bein Bool," above. And that's not to mention their past mixtape work.

They ride for each other in beefs with other people

"I don't feel like the homie taking the Bay sound," YG told MTV News earlier this year of critiques by Mistah F.A.B. "My album don't sound like the Bay."

Even when they turn physical

Punches flew at a nightclub in June after some words had been exchanged between the two camps, and YG and Mustard stuck together throughout.

And stick up for each other when the other doesn't get the recognition they deserve -- like YG's Grammy snub

That is kinda crazy, though.

Or Mustard's sound being co-opted

Like when YG wondered, "'Fancy,' don’t it sound like he produced that sh--?" in a freestyle.

Together, they helped popularize the current prevailing sound in rap

Plenty of videos would have proven this, including "Who Do You Love?"

And have made it work in R&B

Like on the chart-topping DJ Mustard-produced, YG-featuring Jeremih banger "Don't Tell 'Em."

And in pop

On Fergie's comeback single, the DJ Mustard-produced, YG-featuring "L.A. Love (La La)."

They've made hip-hop fans in unlikely places

Stan Lee, the co-creator of Spiker-Man, the Hulk, the X-Men and more, is a Bompton fan.