I have lost a piece I was building
Open build mode and press Bring lost pieces back. It finds anything of yours stranded high above the ground or buried under it and returns it to the surface, wherever it ended up. Pieces inside a mine are left alone.
I am stuck in the scenery
O squeezes you free to the nearest open ground.
I fell under the world
You will be put back on top of it within half a second. If you were under it when you logged out, logging in will seat you on the surface.
A handle will not move
If you are looking almost straight down the arrow you are dragging, the game refuses the drag rather than flinging the piece a hundred metres. Turn the view a little and it works.
My build lost its paint
That was a bug in moving a painted piece with the arrows, fixed on 10 September 2026. Paint applied since then survives being moved.
Something else
Tell Stuart. The world is small enough that he will have heard about it before you finish typing.