A lot of sci-fi is rather grim things. There are interplanetary wars. There are fascist societies with evil overlords. There exists death and deception and so forth. But it’s not all doom and gloom. The evidence could be the beloved (and infrequently adapted) series of books beneath the blanket title https://claytoneatmf.ja-blog.com/13754627/the-best-side-of-science-fiction-novels