The worst for me was the time when I wanted to photograph a machine (something like a high pressure pump) somebody was using to clean the pavement at La Défense. The worker came to me, told me he didn't want "any photographs" and tried to put his dirty and wet hand on my Rolleiflex (I have a lot of respect for workers, and especially those doing a "real" job like this man, but that was too much).

I tried to argue I only wanted a detail of his f**** machine, but I was unable to get the shot and I finally left.