This is more of a "Gimme a break!" than a "D'oh!" moment:
Many years ago, I camped at the site of the (long gone) Phelps lean-to in the Adirondacks. I found a mature birch tree to bear-bag my food. It had a perfect, three-way fork, about 25' up its trunk, and the plan was to get one end of an orange nylon parachute cord up and over it.
I tied a rock to the end of the cord and, after several tries, pitched it through the fork. The rock sailed through the fork but, unfortunately, did not land on the ground. The rock-end fell short and hung a feet feet below the fork. Nothing helped to make the rock-end slide down the trunk to the ground.
I decided to retrieve the line and start over. I pulled hard, figuring the rock-end would come whipping back through the fork but it simply got lodged in the fork. I pulled with all my might (full body-weight) but it wouldn't let go (or break).
I wasn't going to give up yet so I decided to toss the free end of the line through the fork. I tied a rock to the opposite end, tossed it through the fork, and it suffered the same fate and fell short. Nuts. I pulled the cord and, you guessed it, the second rock became wedged. I now had both ends of the cord secured 25' in the air.
Hanging down the length of the white birch, the orange cord was now a bonified eyesore. Being a persistent cuss, I tied another cord to the mid-point of the fouled line, for added length, and tossed it through the fork. Third try was not a charm.
I felt bad about the day-glo orange line draped from the tree but I was out of ideas (for one stupid moment I considered scaling the tree). Like Charlie Brown's kite-eating tree, I had met my match; the birch devoured over a 100' of parachute cord plus three rocks.