For some time now I have wanted to know how to tie a proper butcher's slip-knot. Now, thanks to the magic of the internets, I have learned it. Yay! I am not dextrous, even with practice, so this is not yet a skill at which I am adept - but I do know how the thing is done, and I can do it. My poor sirloin of pork is trussed up tighter than a chicken*.
I saw Ken Albala prepare a salami in SF, and he turned a single length of string into a kind of stocking tied all around the sausage while we watched. It all looked very easy when he did it; 'twas only later, when I tried to figure out in my head how to recreate that, that I figured out instead just what an exhibition of mastery it had been. Hey-ho.
*Chicken-trussing is another thing I learned from the internet. Patrick Stewart may have had something to do with that.