This is hard to explain. Whenever I observe someone doing a task or working with tools, in a silent and focused way, it makes the top of my head itch. I become mesmerized by the concentration and deliberate nature of someone doing something. I saw a guy in a museum once, he was seated at a bench, drawing one of the sculptures on a drawing pad. He would look up, take it all in, and then return to the drawing pad. All that visual information passing through his eyeballs to his brain, then transferred to his hand holding the pencil, onto the paper...I watched that whole process and my head would start to itch.
Back in woodshop class in junior high, we watched a movie on the proper use of tools. The narrator would explain the tools and then stop talking. But the guy in the film never spoke, he would silently and carefully pick up a saw or wrench, and slowly and deliberately use it...I would watch like a zombie with much concentration, and my head would itch.
I still notice it at the library, when one of the volunteer girls are sorting through books and silently and carefully handle and shelve them. Their concentration is mesmerizing, and it makes the top of my head itch....it's the darnedest thing.