I trim my fingernails down really short like this but I do a much better job. I do welding and landscaping and have done construction work most of my adult life. However, I find it odd that his cuticle has never been pushed back in his life. On construction jobs the cuticle will fray at the corners and start being irritating and bleed so I carefully push them back and trim them. I keep my nails short because if I don't dirt and grime build up and make them uncomfortable. That thumb and the hands attached to it have never done any useful labor.