When you write a column, it’s natural to consider your own experiences.  So when I looked at the extraordinary collapse of Derry under Mickey Harte, I tried to think of incidents from my own time with Dublin that would offer some kind of example. What I realised is that, it was not just hard to compare what is happening with Derry to anything that I experienced with Dublin, it was hard even to compare Derry with Derry — the Derry that existed up until eight weeks ago and which won the National Football League. I have never seen anything quite…