BEST book you've ever read?

I want to get back into reading and I'm looking for new recommendations, books that people have genuinely been able to connect with and not just some BS with a repeated trope. What's a book you read that you still think about today and has altered your brain chemistry?

I'm mostly into thriller and murder mysteries but would love to hear about any genre as long as it's a book with a good plot and fast moving, I'm really looking for a new read to start.