75% of Better call Saul involves Chuck which tells me story lines were sparse. So he was jealous of the attention Jimmy got (most likely by unscrupulous means). One or two episodes would have clearly given us that. And, Chuck was not the reason Jimmy was an idiot. Actually, both brothers were idiots. All of the back and forth between everyone else, Mike, Gus, Hector, Taco, baseball card guy, Jimmy and Kim, were not suspenseful, scary, thrillerist or interesting. But now we know for sure Saul/Jimmy is a verified sociopath. The best part was the scenery, thanks for that, georgeous country!