I think there are not many of us who have not done significant...

I think there are not many of us who have not done significant money with ill time exits and greed overcoming rational thinking. The benefit of this experience, is that as a rule, you make this mistake once. I did 300k on a stock, I was holding for more and then watched it fall away with the belief that it would improve. Fortunately it was profit, not that this made the loss any easier. In the end I pulled just under 100k when it should have been in the vicinity of 400k.
The key learning for me was to have my rules and never waver from them and this has held me in good stead for some time now and I have never forgotten my lesson.
NEN will do fine, it's always the exit that is tricky.