Is it a function of getting old that things seem like they only just happened? I was amazed that nobody had mentioned Usain Bolt's 9.58s until I checked and found that it was more than 10 years ago!
A personal one, but my main moment:
Cornwall 18–13 Lancashire, 2015. The first County Championship win for 16 years, avenging previous final defeats to Lancashire, including the two years before. Made all the more emotional as my brother-in-law had been losing captain for the past two years and because I was watching the match with a friend who missed a kick to win the final for Cornwall against Lancashire in 1969, back when it was the pinacle of English rugby. I rushed outside on the final whistle on the pretence of having a smoke to compose myself, only to find a number of equally proud, equally soppy Cornishmen doing the same thing.
The only other two that come to mind:
Eddie Hall winning WSM. Not that I'm a particular fan of his and it must be said that the planets aligned for him with the events in the final, but his reaction when he won made it so clear what it meant to him and how much he had sacrificed to win it that you'd need a heart of stone to not be chuffed for him.
England vs New Zealand semi final win. In the cold light of day, still one of, if not the best performances I've seen England turn in, at the sharp end of the World Cup and the first WC win against New Zealand. Made all the more intense by the scoreboard not really reflecting England's dominance, keeping me on the edge of my seat for the majority of the match.
I'm surprised none of our South African bretheren have stopped by to mention Wayde van Niekerk's world record in Rio. Given my lack of allegiance, I can't say that it's something that I'll be telling any grandchildren about, but it's certainly my favourite athletics memory of the last ten years given the man whose record he broke.