Manchester United boss Sir Alex Ferguson admits he could have burned out if he had continued his obsessive way of managing the club.
He said: "There was a period, maybe 10-12 years ago, when I was obsessed with everything.
"I would come home at night and phone the scouts and other managers, but I was involved in everything at the club. If I'd carried on, I would probably have done myself some damage.
"But then out of knowing how obsessed I was getting, I knew I had to get some other interests and that's when I started buying a couple of horses.
"My wife Cathy said I'd get obsessed with that too and, for a while, I was. But now I just use it as a type of leisure.
"Then I started reading up on wine and playing golf again, for the first time in a long, long time.
"So bit by bit, I realised I had to find other avenues in which to use my energy and not be obsessed with everything that was happening at Old Trafford."