Verb
(idiomatic) to lose one's dignity, temper, or self-control.
To become unmindful of one's own personality; to be lost in thought.
Source: en.wiktionary.orgTo forget oneself is to be happy. Robert Louis Stevenson
In every part and corner of our life, to lose oneself is to be a gainer; to forget oneself is to be happy. Robert Louis Stevenson
There was no solution, save that universal solution which life gives to all questions, even the most complex and insolvable: One must live in the needs of the day--that is, forget oneself. Leo Tolstoy