He started taking yoga and meditation classes to get in touch with his 'inner self'. [=the emotional and spiritual part of himself]
She was her 'old self' again after some sleep. [=she returned to behaving/feeling as she normally did after some sleep]
She helped without any thought of 'self'. [=without any thought of trying to make things better for herself]
(..) And you just assume that Jarvis's operational matrix can beat Ultron's? Jarvis has been beating him from inside without knowing it. This is the opportunity, we can create Ultron's perfect self, without the homicidal glitches he thinks are his winning personality. - We have to. (..)2015 Avengers: Age of Ultron
(..) Oh, I'm sure they do. That's why you let Stark take the scepter. I didn't expect. But I saw Stark's fear. I knew it would control him, make him self-destruct. Everyone creates the thing they dread. Men of peace create engines of war, invaders create avengers, people create....smaller people?... (..)2015 Avengers: Age of Ultron