Suggest me a book that helped you be less pessimistic about life

I’d consider myself a pretty pessimistic person, and It’s something I'm not entirely proud of. I came from a pretty pessimistic family and well, you know, sins of the father. But I hate being the doom and gloom friend that can't help but bring up politics, wars, and how disgustingly evil the world is right now, but how could I not? It’s all I see.

I’m looking for a book that helped you carry a more positive, upbeat mindset in life. Something that helped you have more of a cup half full, rather than cup half empty look on life. In these trying times, I’d really just like to stop dampening the mood with my, “the world is ending” takes.