Anakin admits to Obi-Wan that he has been arrogant and unappreciative of his training, and apologizes to his master. Obi-Wan assures Anakin that he is proud of him, telling him that he has become a "far greater Jedi than I could ever hope to be."
He does. Right at the end. With Luke crying over him and Vader sensing his anguish and pain he had inflicted on all those who had cared for him.
After defeating Darth Vader in the Obi-Wan Kenobi finale, Obi-Wan broke down and began tearing up when he saw Anakin's scars. It was the first time he had seen Anakin's face since leaving him to burn on Mustafar, and so he apologized for everything that had happened.
Originally Answered: Did Ankain really care about Obi-wan during their time together? He has no problem fighting and trying to get rid of him on Mustafar. Absolutely. Anakin loved Obi-Wan like a brother, considered him a great friend, and a valued ally.
Vader responded “I am not your failure, Obi-Wan. You didn't kill Anakin Skywalker. I did.” This allows Obi-Wan to finally accept that Anakin is truly gone and that there was nothing he could have realistically done to save him.
Before he discovered Vader had survived Mustafar, Obi-wan lived with the regret of killing his son, brother and best friend. After, he regretted not killing him and wondered if he had only made things worse by pushing Anakin further into dark side and Palpatine's arms.
The 2022 Obi Wan Disney+ series shows us the very moment Obi WAN discovers Anakin (or Darth Vader) is alive and did not die on Mustafar. There's material in that series that specifically points out he did not regret leaving him alive.
First and foremost, Obi-Wan didn't want to have to confront and try to kill Anakin, we see this all the way until their final conflict in their duel where Obi-Wan pleads with Anakin to not make him do what he knows he'll have to do if Anakin tries to attack from the low-ground.
A very crucial scene in Return of the Jedi established that Obi-Wan Kenobi (a Force ghost by that point) blames himself for Anakin's fall to the dark side. He explained to Luke, “I took it upon myself to train him as a Jedi.
The Jedi Council's Rules on Attachments
The choice to leave his mother at a young age continues to haunt Anakin throughout his life. He is plagued by nightmares of her and visions of her fate. When he eventually saves her from a group of Tuskens on Tatooine, his blind anger at her dying state consumes him.
Obi-Wan couldn't help wishing Anakin the happiness he had been denied, and therefore, he decided to keep the marriage between Padmé and Anakin a secret.
This was addressed in Star Wars: The Clone Wars, teasing that Obi-Wan was at the very least suspicious but chose not to confront Anakin. The animated show also revealed Anakin's jealousy over Padmé, foreshadowing his instability and dependence on her love.
“I have failed you, Anakin,” Obi-Wan told Anakin in Revenge of the Sith. And it's the guilt of that — this feeling that he has created a monster — that Obi-Wan has carried ever since.
The added risk Darth Vader takes in allowing children to live in a situation where he could have killed them proves that he regrets killing Younglings and will avoid harming any more children for the rest of his days, though intense intimidation is a dark strategy to avoid repeating his Youngling massacre.
Obi-Wan knew it was only a matter of time. So, he made the difficult decision to use his learnings and become one with the force, rather than let Vader decapitate him.
And while they're not necessarily wrong, the sudden change makes complete sense from Anakin's point of view. Star Wars: Attack of the Clones shows how problematic Anakin is; he disobeys the Jedi council, slaughters the Tusken women and children, and even goes as far as to marry in secret.
The moment he cut off Mace Windu's hand and Palpatine sent him flying off, Anakin was overcome with a feeling of repulsion, dread, and guilt. He was shocked at what he had done.
Anakin Hated Obi-Wan Because of an Imagined Relationship With Padme. Although that couldn't have been further from the truth, Anakin apparently built up a scenario in his mind, which was only heightened by the Jedi Council's obfuscation in other areas.
For years, Vader hated Obi-Wan, having been struck down by his mentor and left for dead while also believing the Jedi had worked to turn his true love Padmé against him.
Obi-Wan Chose To Ignore Anakin's Marriage To Padmé
Mike Chen's novel Brotherhood reveals Obi-Wan's greatest failing of all; Obi-Wan knew about Anakin and Padmé all along, but chose to keep their relationship a secret.
The Jedi Council was too passive when it came to Anakin's education, and it fostered a toxic relationship with him. He knew that they did not trust or approve of him, and as a result, he lost trust in the Council.
The canonical comic Star Wars: Darth Vader #7 confirms the younglings' deaths caused Anakin grief, self-loathing, hatred and pain, fueling his descent even further into the dark side.
Visions of Obi-Wan. The comic opens during the last moments of Revenge of the Sith, recreating the well-memed instance when a despondent, freshly-armored Vader cries out with a drawling “nooooooo” over how much he's lost.
In the material around the film from the Legends timeline, it's established that by the end of Star Wars: Episode III - Revenge of the Sith, Kenobi was one of the characters who knew Anakin's Sith name was Darth Vader. However, what he didn't know was that he was still alive after Mustafar.