When I was in college, I worked in the library and spent much time reshelving carts full of books, which led me through the stacks, discovering many titles I never would have stumbled across otherwise. A happy little find were the two 1970s bestsellers by Richard Bach: Jonathan Livingston Seagull and Illusions: The Adventures of a Reluctant Messiah.
Both books are philosophical in nature, but they are entertaining and easy reads. They are not what I would call spiritual, in a religious sense, so don't be misled by the word "messiah." They are not about religion. They are novels. They are about nonconformity, and the rewards of being your true self. And they are full of quotable little gems, like this one, which I copied down so many years ago, and find myself remembering whenever I talk to my kids about making friends.