I've died so many times that it's probably hard to have just one most irritating death, but… When I first started playing the game this used to happen to me more that I like to think. I'd lock onto a foe who would fall or as in the case of the geckos run off a cliff or edge and I'd follow them over. What usually happened is I'd be mashing R1 and the lock on would act like a magnet and pull me along with whoever I was attacking. This was more irritating than simply running off a cliff after a gecko. It happened to me when trying to kill an archer on the 2nd tower of the dragon's bridge, it happened in Latria when fighting gargoyles on the bridge and on the winding stairs up a tower and when fighting Maneater, it happened when attacking a skeleton in Shrine of Storms, and it happened in Valley of Defilement up on the wooden planks and in the area above the plague babies.
I think this happened way too much to me especially at first so I try now not to spam R1 if I can help it.
