The first time I used a steel reel I didn't know you were supposed to load from the center. I tried pushing it through as if it were a non-ratcheting plastic reel. I managed to get the entire roll loaded, and later discovered the film was touching itself in many places. Very few frames came out.
Shooting a whole 36 film, opening the camera, and finding it empty..................You only do it once!
Or twice... That happened to me last summer. Had a brilliant morning of shooting on the shores of Lake Michigan, and after I started re-winding the film thought it felt a little bit light. One roll of 120 - not there.
"Often moments come looking for us". - Robert Frank
"Make good art!" - Neil Gaiman
"...the heart and mind are the true lens of the camera". - Yousuf Karsh
The best guide to darkroom disasters was a book by the East German ORWO I found in a university library (along with a whole lot of excellent books on the technical aspects of photography, a far cry from the "just follow the manufacturer's data sheet" given in modern books on darkroom technique). I wish I could remember the title. It was an English edition. Something like "Faults in Photography". Imagine an entire book devoted to all the things that go wrong in photography! It would be a bestseller even today.