Originally Posted by
Zaktar
There was no snap, that is who she was, and you don't have to be cartoonishly evil to butcher innocent people. Real people do and have done that, and they didn't lack nuance, they were human beings. Evil, and damned if you believe in damnation, but not cartoonish.
Like any person she had good impulses and bad, and the people who fed her best impulses disappeared or grew small in her eyes, and in a moment high on destructive power she used it to do something she had clearly rationalized. Once she burned the first innocent person there was no point in stopping. Did you think previously when she talked about burning cities, she was just imagining doing it to real estate, or calmly marching all the innocents out first, or that it was an empty threat? If you rewatch the scene early in the episode where Tyrion is imploring her not to burn the city, she lays out her rationale and it's in character.