I have long remembered an article in a US photomag , back in the 70's ,called "So,you think you know your camera ?"
Great mags then- three pages with ray-traces and pictures explaining why,for exceptional results,"a Lens Hood is essential". Anyway,I digress..

A couple of samples .. 1) without looking at the camera, set it to 1/60 sec,and f/5.6
2) Load,and unload your camera,in complete darkness.

The implication being you were just "futzing " (sp?) around in photography unless you had the "street smarts". The point,if you can do 2), you can close the camera back after removing your exposed strip, and not lose any frames at all..