I find the best ones aren't just about the tech, but how it warps society in ways that feel eerily plausible. Neal Stephenson's 'The Diamond Age' is a masterclass for this. It's less about a single gadget and more about a world transformed by ubiquitous nanotech and the social stratification it creates, especially through the 'Young Lady's Illustrated Primer.' It's the ripple effects that feel most realistic.
For a brutal and personal take, I keep thinking about 'Sea of Rust' by C. Robert Cargill. It’s set after humanity is gone, but the logic of the AI survivors, their resource wars, and the haunting memory of their creators feels like a starkly realistic extension of where competitive, corporate-driven AI development could lead. The tech feels like a natural outgrowth of current obsessions, not magic.