Sewed through my finger tip once. It happened so fast that I didn't know I had done so until I moved my hand and the sewing machine came with it. Amazingly, it wasn't particularly painful, and healed much faster than I thought it would.
I almost poked my eye out with my seam ripper, too. Seam rippers must never be used with real pressure and pointed toward the face. As it was, my eyebrow was grazed.