> But what I realised on revisiting the show a couple of years later is that Walter White didn't break bad. He was bad from the very beginning.
Jesse's girlfriend got him hooked on heroin. Jesse was on a downward spiral and would surely die thanks to her continued interference. Walter saw the toxicity of both the drugs and the relationship and did Jesse a cruel but necessary kindness by letting her asphyxiate. It wasn't ethical, it wasn't humane, but it served a greater purpose (even if it was so Walter wouldn't be without an assistant).
He did far worse deeds for less grounded reasons as the series went on; there are better examples to choose from to make a case of villainy. If anything, what changes through the series is his disconnectedness from everything he was fighting for. As he lost his son's respect, his wife, his family, and his friend, his world became significantly more introverted and he was willing to tolerate greater and greater amounts of collateral damage in the interest of his own survival (since he had nothing left to care about but himself until the ending).