I was about to start this by saying, "you know I'm a fan of Kurt Vonnegut's", then decided to check the facts and realized that I have not, even once, mentioned the author in any article here on WIP. I have a faint recollection of talking about his books on some Youtube videos on the WIP channel (on a list of 7 must-read books and on a list of 7 books that give you an existential crisis), but not here? What the hell?
Let me correct this terrible mistake by first stating that Kurt Vonnegut is one hell of a writer, end of story.
I remember reading Slaughterhouse Five back in high school and thinking it wasn't that good. I mean, the Tralfamadorians are truly innovative and the idea of losing one's grasp on time and bounching around in different eras sounds like fun, but the story lacked something. Therefore, let me assure you that if you've only read Slaughterhouse Five and didn't like it, don't worry - it's not his best book. Not by far.
Instead, you should try pieces like Galapagos and The Sirens of Titan. The first mentioned will definitely make you feel small and insignificant in the universe, and therefore perhaps encourage you to have the courage to live your life to the fullest, because it's doesn't matter where you end up, or how. The latter is both splendidly entertaining in the way it's written, and exhaustingly explanatory when it comes to the great mysteries of Earth.
Because, you know, sometimes you need a kick in the nuts, and sometimes you just want to read something you can't put down. (I mean, who thinks of such things as a man who flies off to space and right into this infundibulum that transports him from Saturn to Earth and Venus and back? Writer inspiration goals, to say the least.)
Then there's of course Harrison Bergeron, a short story so overwhelmingly filled with Randian-Orwellian psychology that it could fill a books series any day.
Kurt Vonnegut - where a killer summary meets superb storytelling.