I'm putting this here in case anyone has the same issue as me in the future.
I was plagued for months by the fact that my rig would not show me how it was deforming as I moved bones. Once I clicked, it would deform the mesh, but only after I clicked.
Finally, I found the solution in the Blender Manual. This isn't a bug, but a feature! If any other newbies have this problem in the future, make sure Delay Refresh is unchecked.
