The stupid questions thread was one of the regular threads on LessWrong 1.0. It's a place where no question is to stupid to be asked and anybody who answers is encouraged to be kind.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
What you might be missing is time. Things don't really "sit still" in spacetime - everything is always moving through time, but things that are moving fast through space are moving slower through time - it's like you have just one speed, but you can point it "out of time" and "into space."
When you travel through a curved spacetime, "sitting still" still means moving forward in the time direction. It's not like the curvature due to gravity creates a potential well that you "fall down." It's more like you're one of those stunt motorcyclists driving around the inside of a steel cage, constantly whizzing forward in a locally straight line, but changing what direction you're pointing due to the curvature of space.