At some point, technically perfect isn't all that relevant or even possible without going all Dunning Kreuger on our a$$e$, but I've had and remember well a few handfuls of experientially 'perfect' runs. Most all were off piste, and several were backcountry.
One less than perfect run was also really cool... about a foot of new, untracked powder, teley gear, no poles... My rear ski dove a bit (pilot error) and got spread out and crossed behind and under the front. Somehow I just kept going, got pointed down the fall line, did a mini royal christy to uncross them, and didn't even break the turn rhythm. No idea how I pulled it off, but it was the 'perfect' recovery. Still puzzles me how the 'cross the rear ski under the front' ever happened and can't figure out how it was even possible, but obviously there was a strong moment of 'suck' going on.