I've always thought if they just showed a bit of encouragement to him he would have been fine.
You're not master - yet. But don't worry, you will be, it's a process. Listen Anakin, I know it seems like a long thing, and you are doing a great job, but everyone goes through this. I went through it....
Instead he just got "You are not qualified. Sit down".
Equally, I don't think Anakin would have lost his shit on Mustafar if he didn't look up and see Obi-Wan standing at the top of the ramp in the ship like an utter bad bitch.
Yeah, I know, took a couple watchthroughs to get it at first but this was their own arrogance really showing. They couldn't be bothered just to show a bit of encouragement.
Terrible parents are more likely to raise terrible off-spring.
And if you are starved of emotional closeness to a father/mother figure and get manipulated by bad influences like Sidious who is most likely a master in manipulation and gas lighting and have way too much power in the force...Pretty easy to land on the wrong track.
The later part after Shmi.
I'd believe her death really made all things fall together.
If the council rescued her from Tatooine and safeguarded her, this wouldnt have happened as it did.
As I only partially know the lore from the movies, did Anakin really have someone to talk to except for Sidious, Obiwan and Padme?
I'd bet as Sisdious being very good as a politician he'd also be excellent at manipulating the low level psyche of Anakin.
Please correct me if I got some lore part wrong as I do enjoy the discussions about SW lore.
I'm not saying that he should automatically be Jedi Master but he should have been treated better. Windu was especially hostile with him several times in the movies.