Full Idea
Striving to become what one already is is a very difficult task, the most difficult of all, because every human being has a strong natural bent and passion to become something more and different.
Gist of Idea
Becoming what one is is a huge difficulty, because we strongly aspire to be something else
Source
Søren Kierkegaard (Concluding Unscientific Postscript [1846], 'Subjective')
Book Reference
Kierkegaard,Søren: 'A Kierkegaard Anthology', ed/tr. Bretall,Robert [Princeton 1946], p.208
A Reaction
Presumably most people continually drift between vanity and low self-esteem, and between unattainable daydreams and powerless immediate reality. That creates the stage on which Kierkegaard's interesting battle would have to be fought.