You two are far enough ahead of me in this show atm that I know I'm not spoiling anything by saying that one of the things I like about "Breaking Bad" is how it ramps. It starts with a premise that makes it plausible for a mild-mannered teacher like Walter White to want to dip his toe into cooking meth -- he has terminal cancer, a pregnant wife, a special-needs son, no money to leave behind to take care of the family when he's gone, and meth gives him a way (really, his only way) to make a lot of money fast so he can make sure the family is taken care of before he dies -- but then, every step of the way, one circumstance leads to another, forcing Walt to react quickly and on-the-fly, pushing him further and further down the slippery slope.
It's really well done, imo. They could've rushed his transformation but, instead, it's a slow boil and they earn it by bringing him there an inch at a time, always with the best intentions but few (if any) good choices (he's basically what you'd call a "reactive protagonist"). I've seen people criticize Walt for making some of the decisions he does but, honestly, there are so many moments (other than two major ones) where I'd say, "What other choice did he have?"
When writing, it's such a balancing act to keep a "bad guy" sympathetic in the eyes of the audience and, honestly, I think "Breaking Bad" is a masterclass in doing so.