I know Dany lost a lot of fans after her behavior in ADWD, and I’m not going to pretend her actions in Meereen were flawless because that’s far from the case. But I do want to discuss the reasons why (I think) she behaves the way she does.
(ADWD spoilers below, obviously.)
First off, this is a fifteen year old. She’s an adult by the standards of her society, and thinks of herself as an adult, but mentally she’s not quite there - and that’s understandable for someone who was raised by a brother who was cruel to her and was sold to a Dothraki khal at the age of thirteen. From a psychological standpoint, I’m surprised Dany didn’t snap much, much sooner.
But she doesn’t; up until ADWD she exhibits a maturity that is far beyond her years and experience. She assimilates into Dothraki culture, makes the best out of a potentially horrible marriage that she didn’t want, holds herself together for her khalasar after losing her only family again - I could go on, but I think you get the point.
Eventually, however, that amount of mental stress is eventually going to have to be released. The final straw that cracks her emotional armor comes at the end of ASoS, and I think this line sums it up:
She was Daenerys Stormborn, the Unburnt, khaleesi and queen, Mother of Dragons, slayer of warlocks, breaker of chains, and there was no one in the world that she could trust.
Up until this point, she has always had someone to look out for her. Viserys protected them both when she was young, and while he was mean to her he was still a guardian, a family member. When Viserys died, Dany was Drogo’s wife, the mother of his heir, and under the protection of his khalasar. No reason not to feel safe there. After Drogo dies, she’s focused on her dragons, and she still has her tiny khalasar and Jorah to protect and advise her.
But in Meereen she loses her best friend and right hand, and has little else to show for it.
Yeah, she has an army, and her Dothraki are still around. She has Missandei and Barristan, but she hasn’t known them very long yet. But what’s crucial here is her realization that if she can’t trust the person she trusted most - the person she let command her armies, guide her military decisions, and be her closest advisor - then she really can’t trust anyone.
Which means there’s no one to protect her. and she knows it:
Was there no one she could trust, no one to keep her safe?
Dany is now a fifteen year old who feels like she has no one to protect her in a world where people are frequently trying to assassinate her, on a mission that will involve battle after battle that may end in defeat and death. She’s in a city where most of the inhabitants hate her, she is losing control of her “children”, and she doesn’t know if she can trust a single person in her employ.
So can we really begrudge her a bit of teenage behavior? A fling with a man she knows is bad for her but wants anyway? Some political mistakes? (And yes, I know her age doesn’t excuse the fact that she’s causing harm to the people of Meereen, but I think the reasoning behind her poor decisions is understandable, especially given that Meereen is a political quagmire that most adults would find difficult to manage.)
To me, ADWD is an example of a teenager who has tried so hard to be strong finally breaking down, and I find it hard to criticize her for finally acting her age. I also think that in the books to come, we’ll see her regain the strength she displayed at the end of AGoT and refocus on her overall mission.
Or she might be broken for good; we just don’t know. After seeing her finally ride a dragon, though, I think her breakdown in Meereen was only temporary.