5. Watching Jane Die
One could argue that Walt wasn't necessarily an evil character because very few of his murders came by his own hands and those he did directly kill had first tried to attack him, as in Krazy-8. However, there can be no excuses here, we Walt breaks into a sleeping Jesse's room, tries to wake him, accidentally rolls a drugged-up Jane out of her recovery position and watches on as he chokes to death on her own vomit. This had more serious implications later on, when Jane's devastated father loses concentration while at work as an air traffic controller, leading to the deaths of 167 passengers on the Wayfarer 515 and JM 21 flights. If failing to help Jane from choking to death wasn't diabolical enough on its own, his (albeit unintentional) responsibility for the deaths of the airline passengers certainly was.