For reasons I do not know, being a noob in blender. I have all these grainy effects on a surface that should be smooth.
Additionally. It seems like when I take a face of my object and extrude it inwards, a “invisible” face stays in the place of the face I just moved, so I can move the selected face down and up. But this invisible like replica of it stays where it was, I cannot select or move this face. It is annoying.