Moments of tranquility is experience when one is in harmony with self and with the world. My first experience with experiencing tranquility was with Transcendental Meditation; an experience beyond happiness. It was an experience beyond constraints of space and time, and existence of me as a person.
Going forward, I had similar experiences each time I was deeply involved some work; reading, listening to music, talking, …. work that I feel like doing rather than; not some work imposed on me. When you do something which you feel like doing, it is not pain, it does not hurt. It hurts when there are expectations are attached.
Think of a work that you would do if you have nothing left in this world, no reason to even exist but you still exist. Think of a work that you would do if you have everything that you can think of. Think of a work that you would do in state of absolute happiness or utter despair. You do that work, not because it gives me money, power, position; not even the satisfaction of having done something. Think of a work that you would do even if it makes no difference either to you, or to the world.
World may be real, or an illusion; I don’t care. What I do may pay me or hurt me; I don’t care. I do it because I feel like doing it. I do as best as I can. State of mind when I work like that is no different from the state that I reach with meditations. It is state where I am neither happy nor sad. It is a state of pure existence, absolute tranquility; a state in which I am in complete harmony with myself, and with the world