The idea that excites me the most concerns the two greatest puzzles in science: the origin of the universe, and the origin of consciousness. The origin of the universe is what I do for a living, working on string theory. But I am also fascinated by consciousness.
We will always be attracted to the situation or person that we need, in any given moment, in order to learn whatever lesson that we need to learn. The most important thing is to learn the lesson quickly, let go, and then move on.