I always try to make NEW mistakes.
A couple of years ago, a friend and I went on a photo hike. I loaded my F3/ MD-4 combo with Arista 400 EDU.
Loaded my F3 thousands of times, yadda yadda yadda....
Did the hike, took 36 interesting shots.
Back to the car....
Rewound the film...well, that went kinda quickly!?
Open the back of the F3, and discover that the film leader had snapped off right near the cassette after loading.
If I had been monitoring the rewind knob, I MIGHT have noticed it not moving....
Not my fault, really...I'd never had film break before...but just another way Mr. Murphy can give you the finger when you least expect it...gotta be vigilant!