The Scotsman has been retired since the 2012-2013 season, when his team last won the Premier League.
The 82-year-old lifted Premier league titles and 38 trophies overall, including the Champions League twice.
"Yeah, I miss it sometimes," he told BBC Breakfast.
"I think the first year after retirement, I went to the European final and I said to Cathy 'this is what I miss' - big games, the European games.
"So then I went to most of the European finals because I find something I can relate to, something I would liked to have done every day. Because these are the big events that United should always be involved in."
"Fortunately my memory is quite good, pray the lord and touch wood it will stay that way," he added on his health, considering he suffered a brain hemorrhage in 2018.
“I read a lot, I do quizzes, and I think that helps, there is the YouTube quizzes with 100 questions and if I don't get 70 per cent I'm struggling."