I'm pretty hard on my socks and I have many ways of wearing them out. I've walked holes in the heels, holes through the bottom of the foot, and poked holes through the toes. I loved and wore a pair of Regia silk lace ones to the point that the lace was threadbare on the foot. I've even had socks go missing in the wash. (Jim does the laundry and it's worth the loss of a hand knit sock to have a husband who does laundry. Really.)
But today I put on a pair of socks that are wearing out in a whole new way.
This is a shot of the heel flap, and you can see that the stitches are laddering up. I'm gobsmacked. I can only think that the stranding holding the stitches wore through and set them free.