be oneself—behave in a way that is natural, especially in contrast to the affected manner:
- I wish you wouldn’t act the sophisticated lady. You’re far nicer when you are just being yourself.
be oneself again—be in one’s normal condition of mind and body after an illness, emotional stress, etc.:
- After such a long illness, it’s good to be myself again.
Note: Neither expression correlates in meaning with the phrase be full of oneself—be impressed with one’s own work; be too proud of oneself:
- Karl is so full of himself. He is a good designer, but I’m so sick of his personality.