I don't feel frightened by not knowing things, by being lost in the mysterious universe without any purpose - which is the way it really is, as far as I can tell. Possibly. It doesn't frighten me.
"Horizon (The Pleasure of Finding Things Out)". Documentary (November 23, 1981), later published in "No Ordinary Genius: The Illustrated Richard Feynman" edited by Christopher Sykes (p. 239), 1994.