I miss the days when there were events to be genuinely excited by like, in my case, the first flights of Concorde and the first moon landings. Now people seem to wet themselves over the launch of a new iPhone.
You can learn from it. I'm sure you already knew that.
Well for me I look back at the good memories and I smile makes me feel good.
I look back at the bad memories and see what I could have done better. ; )