Humans are so strange with their penchanct for the arbitrary, particularly with dates. 5 years means something but not a whole lot. Than 10 is fairly large for some reason. Then we really just forget everything else till it hits 25, then 50. By which time that which will people will "never forget" has mostly been forgotten. That and the insane reasons, bottom to top, for why all the insanity occurs in the first place. A strange species indeed.
"You have enemies? Good. That means you’ve stood up for something, sometime in your life."