Sister by Rosamond Lupton. For some reason I can't make myself read it a second time as I'm almost scared to find out that the ending means the opposite of what I think/hope it means.😂
Non-fiction, one of the best books I've read, The Less You Know The Sounder You Sleep by Juliet Butler. It's about conjoined twins who grew up in the Soviet era. When I found out something about one of their friends at the end it really shocked me in terms of how my pre-conceived ideas had made an assumption about someone that was completely wrong. A tiny aspect of the book but I guess it had a profound impact on me due to that aspect alone.