It literally made no sense why she went 'mad' and started burning people in King's Landing.
I've heard some theories why. Like cleansing the city, blah, blah, blah...
But she's a foreign invader. And as Tyrion has tried telling her multiple times, you got to win over the Lord's of Westeros.
What she did, when there was no tactical advantage to do so, was just a huge and very stupid mistake by her. And frankly, one, that didn't even make sense.
It'd been better if there was some justified reason for doing what she did. Burning King's Landing. But there was NONE!
It felt out of left field, and its why a lot of us just think its jumping the shark television.
Just intimidating your way to power, and staying, just doesn't work. It didn't work for The Mad King.
And she seemingly understand that early on, but now just doesn't?