Loss of potential sharpness.

O.K.  here one and I told myself I would not post too many gripes here...   Fella is walking along the route that I like to take while I head over to my doctor's appointment.  I was maybe a good 100 feet behind and getting closer as he continued to stop and start.  I was using a Nikon and a big lens... could be a 24-70 2.8?... just noticed the wide front element... so he was constantly chimping. When I got to about 12 feet he noticed my 6X7 camera and at first must have thought it was a digital and was about to ask a question, but then thought different and turned around and kept walking.  Now this was uncomfortable... I'm needing to slow down because this guy thinks I'm tailing him and checking his work.  I noticed that he was almost randomly playing with the modes on the camera and he had an awful hammer press method on the shutter button.  It was 2pm and the area we were walking in was in shadows from trees.  I could only guess that he didn't know to set the ISO higher or that the camera may have been selecting slow speeds?  Almost to my turn off and the guy was still chimping almost every shot I had to ask...  "Excuse me, I couldn't help to notice, but... " He looked up and said abruptly... "Don't need your help, It is digital technology, different type of photography you know!"  Well, I know when I'm not wanted.  Coming back later from my appointment, I pass a near by field where kids are in some sort of track and field trials or such and there he was, still struggling with that camera.  Still hammering at the shutter button.