The good thing about Danzo is that he was extremely loyal to Konohagakure...
The bad thing is, he was so loyal to Konohagakure that he literally fucked up everything else.
Dude fucked up with so many ninjas in 3rd world war, was responsible for Uchiha massacre and when he was finally the next hokage, he fucked it up in the 5 kage summit room as well when he was putting Mifune on a genjutsu in front of the other kages. Just why? He had everything, so why was he endangering his position by pissing off the other kages in front of him?
Danzo was highly scheming but I cannot grasp how he made consecutive bad decisions over and over again.
His worst decision wasn't even reckless in kage summit arc, it was plain up stupid. Let's say Danzo was being a typical ruthless villain when it comes to his previous decisions but the one in kage summit arc is still so laughable, it's just so dumb.