A year or two into my climbing career, I'd only done a dozen or so abseil retreats. For all but one of them, the decisions I made were the right ones, and I did as much as could to keep myself and my partners safe. For the one which didn't go quite so well, I made one bad decision: I chose to trust a single anchor without properly testing it in order to save some time (retreat from first stance of multipitch route, lowered partner from belay then abseils off a single thread). This was the result of that bad decision:

The rock thread snapped. I fell ~5 metres vertically, landed on my feet on a small grass ledge, crumpled and rolled off the ledge and then proceeded to tumble are over teacup down a steep heather/rock/scree slope. My partner managed to grab hold of a rope to help slow me down, and then secure me to an anchor, but not before I’d fallen 15-20 metres down the slope and took a 2-3m fall, landing head first (luckily with a helmet still on).

While I sustained a few injuries, (two sprained ankles, some torn ligaments, cuts bruises a mild concussion and a damaged vertebrae) the main damage was to my confidence when on a rope. Something which took years to regain.

As a perpetual optimist, I'm thankful I got away with such minor injuries. Had it not been for my helmet, remembering how to break roll and the quick actions of my climbing partner, things could have been a lot worse. It’s no exaggeration to say I used up at least one of my nine lives that day.