Sir Alex Ferguson says he is "grateful for the three years extra" he feels he has had after surviving a brain haemorrhage in 2018.
The legendary former Manchester United manager made the admission before this month's release of a new film about his life.
Directed by his son Jason, 'Sir Alex Ferguson: Never Give In' recounts his journey on and off the pitch, the support of his family, and the recovery from his health scare.
And the 79-year-old Scotsman believes that audiences "may be quite startled" by the way he comes across in the documentary.
"They may say, 'he wasn't like that as a manager, he's a different guy, he's human'."
In a wide-ranging and rare interview with BBC Sport, conducted at Old Trafford, Ferguson
- Revealed he was "terrified" of losing his memory and voice after his devastating brain haemorrhage, and is "very fortunate" to still be alive.
- Explained his opposition to the failed recent proposal for a sealed-off European Super League, saying "the real reason for football is that the smallest guy can climb to the top of Everest... we can't do without that".
- Praised the latest manager to try to replace him at Manchester United, his former player Ole Gunnar Solskjaer, for "giving young players a chance... he really has done very well", and highlighted the "drive" of Pep Guardiola and Jurgen Klopp.
- Said he believed he would still succeed if managing today, but that current players are "more fragile, they need more care... it's become a more protective life nowadays", and social media was a "terrible problem".
- Said he was "so proud" of Manchester United striker Marcus Rashford for his campaign for free school meals.
Ferguson, who retired from management in 2013, had emergency surgery for his brain haemorrhage on 5 May 2018, and was in intensive care for several days.
The film, which will be shown in cinemas and on Amazon Prime, starts with the audio of the 999 call that Jason made after his father fell ill at home.
"I tried to get out my bed and just collapsed," said Ferguson.
"I was very fortunate because I fell against a shoe rack, and all the shoes fell out and made a noise, and Cathy was downstairs.
"She came up and got me sat up against the wall, and that's the last thing I remember."
Following his operation, Ferguson said his greatest fear was losing his memory.
"I always depended on that. And then my two grandsons were in with me, and all of a sudden I stopped talking, I just couldn't get a word out.
"And at that moment I was a bit terrified to be honest with you.
"And I'm starting to think, 'What are we going to do now? You can't talk, has my memory gone?' And then the speech therapist started, she was fantastic, got me to write all the names of my family, all the names of my players, and then about 10 days later it came back.
"All of my life I have appreciated the NHS, none more so with that experience, they were fantastic. And I owe it to them really."
When asked how the ordeal had changed him, Ferguson replied: "Probably not taking things too seriously in terms of knowing that you're vulnerable… if I go tomorrow I'll be grateful for three years extra I had. That's a feeling I've had for quite a while now."
'My proudest moment'
With Ferguson's working-class identity and Glasgow roots a central theme of the film, it features previously unseen footage of him leading an apprentice march in Glasgow in 1960, when the shipyard workers went on strike to demand higher pay.
"When Jason came to me with the clip… that was astounding," he said.
"I said, 'where did you get that?' That was probably my proudest moment at the time, because apprentices in those days weren't paid well… the cause, to get them better conditions, always lives with me.
"It will cling to me all my life because how you're brought up lives with you, the important things that your mother or father taught you… as you get older your own personality maybe changes. But these things are really the foundation.
"I never used reflection as part of my management, always looked forward.
"So the reflection… thinking about some of the players you had and some of the triumphs and defeats was quite powerful for me."
The film - which Jason said he wanted to be a "very personal and intimate" portrait of his father's life, also reveals the appreciation Ferguson feels for his family, and especially his wife, Lady Cathy.
"Management is such a sacrifice that you don't have time for family, you don't have time for your friends," he said. "I didn't want to fail. I couldn't fail, so that was always a driving force for me, and I needed a wife that recognised that and lived with it, and that couldn't have been easy for her. She brought the boys up."
'Every club should have that dream'
Ferguson won three Scottish Premier Division titles and the European Cup Winners' Cup, among other trophies, during eight years with Aberdeen.
He then went on to become the longest-serving manager in Manchester United's history, winning 38 trophies in 26 and a half years, including 13 Premier League titles and the Champions League twice.
With more than 550 hours of material gathered for the film, it ends with the 1999 Champions League final, when United scored twice in stoppage time to claim a famous victory over Bayern Munich and complete the Treble, having already won the Premier League and FA Cup.
The future of the competition was threatened last month when 12 clubs, including United, tried to launch the European Super League
The breakaway plot failed, but sparked fury among United's fans, some of whom stormed Old Trafford in protest at the actions of the club's despised American owners, the Glazer family.
Ferguson declined to be drawn on the controversy surrounding the owners or the fan protest, but did make clear his opposition to the idea of a sealed-off 'super league', with access restricted to the wealthiest clubs.
"As a player I played in European football for Rangers and Dunfermline," he said.
"And then as a manager I took a provincial club, Aberdeen, and beat Real Madrid in the [1983 European Cup Winners Cup] final in Gothenburg. That is a provincial club, fulfilling its dream.
"Every club should have that dream to achieve what Aberdeen did. So that's the answer.
"You cannot ever forget that the real reason for football was that the smallest guy can climb to the top of Everest, and that's the best way I can put that. We can't do without that really."
When asked if he would find it harder to be a manager in today's game, where power has shifted towards players and their agents, Ferguson said: "I personally don't think so.
"I think I had something in me that was bound to get me somewhere in life. I'm not being boastful, but I think I had that personality to do well, the drive and the hunger and the energy. Even when I got into my 60s I wanted the players to really see my energy.
"My experience in the last few years at United would reflect the fact that they are more fragile, they need more care.
"The players I inherited at Aberdeen and Manchester United were strong, were powerful, and it's changed because it's become a more protective life nowadays. I was very lucky to inherit the kind of players that I did in my earlier days."
And he had special praise for Liverpool manager Jurgen Klopp and his counterpart at new league champions Manchester City, Pep Guardiola.
"I think there are young people out there with a drive like you see with Klopp for instance, and the drive he's brought to Liverpool, and Pep Guardiola with the job he's done at City… there is a place for people with the right credentials, and the right material to do well.
"And I take your point what they're up against today, because you've got social media which is a terrible problem at the moment. And you've also got the role of agents… and there are obstacles. But the good ones will find a way."
Praise for Solskjaer
United have not won the title since Ferguson's last season in 2012-13 and Solskjaer is the first manager to secure back-to-back top-four finishes in the league since the Scot retired. United are currently second in the league and through to the Europa League final.
"Even as a young reserve, even when he was on the bench… he would take notes of the training sessions. He had a will that he wanted to be a manager, and at a club like Manchester United, it's a result industry, without question.
"If you don't get results there's questions to be asked. He is getting the results, he really has done very well. And what is really important for this club is to introduce young people, and he's given young players a chance.
"That will always be the foundation of Manchester United, from Matt Busby, from Alex Ferguson and to what Ole is doing, the young guys, if they are good enough, play them. Never a problem at this club."
England international Rashford, 23, has used his platform to campaign for the provision of free school meals in England during holidays and other support to low-income families, prompting major changes in government policy.
"When he did what he did I phoned him right away," said Ferguson. "And I thought what he was doing is an example for a young person to give to all the rest of them in this industry, which most of the top players are doing very well.
"For Rashford to do we he did, for a young person, I was so proud of him, I really was. I think everyone was and he's not got carried away with himself. He's still trying to do an honest job as you would expect from him."
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