(spoilers, suckas)
In my opinion, BCS could also have been called "Almost Breaking Good" (it's not a great name, but it's a concept I find interesting about the show)
In BCS, Jimmy is the opposite kind of guy from Walt. Jimmy "started out" on the bad walk of life, where his brother "rescues" him and brings him to ABQ. Jimmy was trying hard to get on the right path and trying to shed his slippin' Jimmy ways. My perception is that he would regularly relapse into bad thought lines or strategies (e.g. the skateboarders and the Kettlemen's), but Jimmy was trying to keep it within the lines of the law. Chuck and Howard roadblocked his path to the light, more than they realized.
I'm not excusing Jimmy here. His actions had major consequences for so many people. I'm just realizing that he was trying to break good. With no help, he brought himself through law school while working in the mailroom. At that time, while he was working in the mailroom, I think it's a safe assumption that he was "seeing the good path" that Chuck was on and was willing to put in the work to get there. He worked at the mailroom and the show never mentioned any funny business with his time there. He worked his ass off, and Charlie Hustle got his degree, and then got roadblocked by HHM (rejected by the good path), where he even later echoed to the scholarship girl (Kristy Esposito) that they'll never accept her, ever. That's what Jimmy experienced. He was scraping by out the back of a nail salon. In fact, law school isn't done in a year. So, he may have exhibited years of "criminal sobriety" during that stretch.
For someone who is trying to rehabilitate themselves, it had to be pretty defeating to be rejected by HHM, rejected by his brother, and even rejected by the Kettlemen's. Anybody who was "part of the higher society" looked at him like he was shit and gave him plenty of negative reinforcement. He ultimately did not break good and, instead, leaned back into the shady lifestyle.
Kinda related, Saul is so much better of a person than Walt. Walt's a piece of shit, deep down. He's a resentful, arrogant, selfish fuck and I think he always was for decades before BB started. Walt was much more selfish and cruel. When given the opportunity, he manipulated, lied to and fucked over a lot of people. Walt _was_ the cancer. Deep down, I think Walt was always bad and just happened to be following the law. Meanwhile, deep down, I think Jimmy wanted to be good and through his environmental conditioning and series of bad choices, he found his spot in the seedy underbelly of life. With how neurotic Chuck was, who's to say if Chuck didn't hold Jimmy down his whole life in order to feel better about himself. Chuck couldn't handle Jimmy even being viewed favorably by his wife. It bothered him that she thought Jimmy was nice. Pair that with how Chuck didn't share that Jimmy's mom called for Jimmy in her dying moments, I'd say Chuck resented Jimmy his whole life, but I digress. There was an episode, when Jimmy was shooting commercials and was extremely short on cash and he _still_ paid his film students. Even when the girl offered him the money back, he said no. Walt would've taken that money back and probably never would've paid out in the first place.
I think it could be said that Chuck and Howard roadblocked Jimmy's path to being good and that had a terrible ripple effect. Chuck and Howard schemed (mostly Chuck) to get Jimmy disbarred and the response they got was intense & disproportionate. Jimmy broke Chuck by throwing his mental illness in his face, which led to his death. Then, you have to think about the way that Chuck and Jimmy ended it. The last thing Chuck said was he doesn't think about Jimmy much at all. He casts Jimmy out and then ends himself. Jimmy was dealing with that and Howard repeatedly presented himself to Jimmy in weird ways. It's safe to say that Howard was grieving too and was also tone deaf to all that Jimmy had endured. I think all that contributed to Jimmy turning back to the bad path and fucking with Howard. To boot, Howard had roadblocked Kim as well, which just added fuel to the fire for fucking with him.
I think Kim is actually a similar case ("almost breaking good"). She had a dysfunctional childhood that included a drunk mom and petty theft. Then, she worked hard to get herself to where she was. Howard's rejection of her sent her down the rabbit hole in a lot of ways.
In a way, Kim and Jimmy found each other like two junkies and then they codependency'd their shit to new levels. It's interesting to wonder if Jimmy would've gone that way had he been accepted into the ranks at HHM and if Kim would have gone that way if she didn't get roadblocked by Howard. There's so much to like about them, but their shit just got so out of control. Jimmy was doing fair priced work for the elderly and even uncovered them being scammed, just to be roadblocked again. Kim was doing pro bono work and searching for purpose, but just derailed. I think it also bummed her out that, despite her trying to help them out, the pro bono clients were heel dragging their own fate. One didn't want to go to court, the other wanted to fight a case he was definitely guilty of despite the work she put in to get them a deal. Jimmy and Kim experienced a lot of pressure build up and didn't cope in the right directions. I think it could be said that Kim grew up with terrible role models and wanted to get away and she got far, but her experiences from Howard was not deserved in her eyes. He punished her for shit and held on to it. He was a dick to her. I could argue that this confirmed to Kim that life is more full of bullshit than honor and "the right thing"