There are a variety of reasons for me.
Simple camera work is probably the biggest thing for me.
My favorite films are 400 speed C-41 process films (color print and chromogenic B&W negatives). They have so much exposure latitude that I don't sweat about overexposure. This shot http://www.apug.org/forums/groups/5-...15-asis-2.html was done with am RB67 F4@400 Fuji npc160. About 3-stops overexposed compared to the sunny-F16 rule.