Not an arborist story, but involves tree climbing. Early on in my cat rescue hobby, got a call from a lady to rescue a cat. Got there, cat was 35 feet up skinny pine tree, no good limbs until cat. NP, I tell lady, I will use my spurs (only had used them about 3 times previously). Also had my nearly brand new tree motion harness. Started up tree, but my spurs kept slipping out and I would hang against tree. I notice my harness felt weird, like it was riding very high. I keep going up out of stubbornness, but soon start running out of energy. I also seem to be strangely out of breath, can't seem to breathe very well as my harness is riding high, constricting breathing. Gets worse each time my spurs kick out and I hang in harness. Finally, at 25 feet, I wrap my arm around a spindly limb, and decided I need to come down. I get my rope out, and my Figure-8 descender, but my oxygen-deprived brain can't make any sense of it. I start to panic a bit, yell at lady to call 911 (as if that would do any good, we were in the boonies). Her mouth is hanging open at my stupidity, but she makes the call. I am hanging there, getting dizzier by the second, when the limb breaks and I slide down the trunk about 10 feet, halt, then slide the rest of the way. Get a real good nasty scratch up my chest from a stub, ribs feel like they have been hit by a hammer. I hit the ground, lay on my back and gasp for breath. 911 person from phone is asking if I am OK. I look up, and the cat says "To Hell with This!", and starts coming down the tree, makes it to the ground, and takes off to the house. Lady looks at me like I am crazy. I apologize to lady and take off.
On drive back, I figure out what happened -- I had forgotten to belt my leg straps, so harness was coming up around chest, constricting breathing. I delete helmet cam video as it is too much a monument to stupidity. I tell my brother this story later, and we die laughing about it. Why I didn't just whip out a nylon loop runner (several on my harness) and form something for me to step in, I have no idea. My stupidity quotient was sky-high that day.
I have never used spikes since then, and learned how to do stem climbing with ropes, lanyards, loop runners (which I have had to do on 3-4 rescues since then and am now a semi-expert at it.).
The End.