Eugen Herrigel said this quote

This exquisite state of unconcerned immersion in oneself is not, unfortunately, of long duration. It is liable to be disturbed from inside. As though sprung from nowhere, moods, feelings, desires, worries and even thoughts incontinently rise up, in a meaningless jumble.... The only successful way of rendering this disturbance inoperative is to keep on breathing quietly and unconcernedly, to enter into friendly relations with whatever appears on the scene, to accustom oneself to it, to look at it equably and at last grow weary of looking.