Heh heh. I wrote an essay once on the proper use of the hammer. My thesis was that you can best tell an expert, seasoned mechanic by how he uses his hammers (and his torches). He knows which hammer to use and how hard to swing it. An eighty-year-old guy helped me once to change the monlithically rusted front brakes on my plow truck. His work was a masterclass in the use of the hammer. He kept a big oily pile of assorted ball peens right there by his side.
I used to write overhaul manuals for Naval weapons systems. (NOT in the Navy, a civilian job). The Navy guys had to sign off on our manuals, and they were VERY fussy. One time, I couldn't tell from drawings or field/engineering reports just how hard a pin had to be hit to get it out. I asked the Navy guy whether he thought it was a job for a little hammer or a big one. He said, " I dunno. It's YOUR job to know this stuff." (I was 22.) Next time I brought in the draft for review, I had changed the text to read, "Strike the pin lightly with a heavy hammer." He looked at me, smiled, and said, "Perfect."