I have carried a knotting-related grudge for well over thirty years concerning the figure-of-eight... a very simple knot as you will of course agree.
It goes back to a Cub Scouts (the junior Scouts group) meeting where there was a knotting competition. Each "patrol" were given a short length of rope, formed up in lines and the person in charge called out the name of a knot. The boy at the head of the line had to rush up and demonstrate his knot of that type - first to complete it scored a point for his Patrol.
The figure-of-eight is very simple. So simple in fact that I did the knot as I ran forward and presented the completed knot as I arrived. I was accused of cheating, ordered to do it again and we lost the point, much to my annoyance.
Young lads can carry grudges for an immeasurably long time. My wife has just said..."How old were you? You have been carrying this thing for nearly forty years!!!"
Mind you, it did have its advantages... our washing lines are perfect round turn and two half hitches. It bugs the heck out of me when a neighbour or workman takes them down to move a ladder or scaffolding across the garden.