From I. Asimov: A Memoir:

If I want to recall peace, serenity, pleasure, I think of myself on those lazy summer afternoons, with my chair tipped back against the wall, the book on my lap and the pages softly turning. There may have been at certain time in my life, higher pitches of ecstasy, vast moments of relief and triumph, but for quiet, peaceful happiness, there has never been anything to compare with it.

I couldn’t have said it better myself.