Physicists say that when slow people watch fast people, the fast people shrink. It's called the Lorentz contraction. But when the same fast people watch themselves, they don't shrink. A contradiction?
So which is it? do people actually shrink when they go fast or not?
Physicists found a great way of answering that. They threw up a smokescreen and called the contradictory phenomena "relative". Then, to "explain" what relative meant, they replaced time and space with a woolly spacetime. Because spacetime is so woolly, the physicists felt safe in abandoning actual spatiotemporal reality and replacing it with relative spacetime reality.
But let's face it. Should we really think that words like spacetime, and relative, are more than just circular, self-referencing metaphors?
No. We are just as much puzzled by the "Lorentz contraction" after we thought of spacetime, than we were before we thought of spacetime.