My recent bloopers have both been related to bulk rolling as I had let my photography lapse for a couple of years was simply out of practice.
1. I rolled a whole 100' tin of Tri-X (so about 19 rolls) backwards on the spindles, which means, of course, that they won't load in the camera at all. So, I had to go into the darkroom and, one by one, take the film off the spindles, re-tape it on the spindles going the right way, and then wind it back on the spindles manually (i.e., trying not to touch the film except along the edges), etc. What a pain!
2. Sadly, despite successfully re-winding all 19 rolls, the train wreck with that tin of film didn't end there. In my frustration at re-winding all those rolls I neglected to tape them sufficiently well to the spindles, so ... almost every roll of that tin would detach from the spindle when I reached the end of the roll, necessitating taking the whole camera back into the darkroom to unload the exposed film. This meant that I had to carry two bodies every time I went out shooting as otherwise my day would be over when I reached the end of the first roll. What a pain!
Thankfully all this self-inflicted pain is in the rear window now as that tin of film is FINALLY done. And I really only lost one roll to serpentine stress marks from unloading the film from the M6 too sloppily. Lesson(s) learned, I hope.