Northern Ireland boss Michael O'Neill has admitted that he under-achieved as a player and now uses that frustration to drive him on as a manager and inspire the current internationals to fulfil their potential.
In a candid interview with the Belfast Telegraph, O'Neill, who will take Northern Ireland to the Euro 2016 finals later this year, revealed that he will always feel as though he didn't do himself justice as a footballer, how he would have approached playing in a major tournament if he had been given the chance and the way in which he will break the heartbreaking news to those who don't make it into his squad for France.
Since securing qualification for the European Championships last October, O'Neill's feet have hardly touched the ground.
He's dealt with hundreds of media requests and received more letters than Santa Claus asking him to attend functions or charity events across Northern Ireland and beyond. He rarely turns anyone down.
When we meet in Belfast's Europa Hotel, the in-demand 46-year-old is preparing to go to Queen's University for a question and answer session in front of an adoring and admiring crowd.
All this is combined with his job as Northern Ireland's hardest working boss ever, travelling around the UK every week to watch players at Premier League level in front of 75,000 spectators and reserve games with only scouts beside him for company.
Then there's the analysis of the opposition and a constant desire to come up with fresh ideas which can make a difference to his team in France. That's before you even get to the Northern Ireland internationals themselves, in which O'Neill has flourished over the last 18 months.
At Easter he finally got a break with his family, taking wife Bronagh, originally from Portadown, and daughters Erin and Olivia to Barcelona. Of course there was football involved with all four enjoying a match at the Nou Camp.
O'Neill's only previous experience of the iconic venue was completing the stadium tour. How he would have loved to have played in that venue.
Joining Newcastle from Coleraine in 1987 as a gifted teenager, the football world was his oyster. Early on the Toon Army worshipped him as he scored goals and outshone another young talent called Paul Gascoigne.
Two years later he joined Dundee United for a club record fee of £350,000 and again had his moments but as he acknowledges not enough of them, though on occasions injuries did not help. O'Neill had touch, vision, passing ability and an eye for goal but, despite winning 31 caps for his country, never reached the heights his quality should have taken him to, with underwhelming spells at Hibs, Coventry, Aberdeen, Reading, Wigan, St Johnstone, Portland Timbers in America and Clydebank before his class showed for Glentoran in the Irish League.
Talking about his career on the pitch, O'Neill said: "I always feel like I under-achieved as a player and that never leaves you. You don't get over that. That will always be there. I'll wake up when I'm 60 and I'll feel that."
Asked why it didn't work out as he had hoped, he said: "I don't really know. Things conspired against me a little bit. I just felt that I didn't achieve as much as I should have done as a player. I never got to the level that I could have done with the ability that I had.
"It is something that drives me as a manager. I want to be the best that I can be and it also drives me to help the Northern Ireland players get as much out of their careers as possible.
"That's why I was so delighted to see Kyle Lafferty turn his situation around. A couple of years ago I was looking at Kyle and it seemed like he had no direction where he was going club-wise and international-wise. Then suddenly he gets focus and applies himself and look at him now. When he plays for us he is excellent.
"The Euro finals give our players a massive opportunity. If you go to tournaments all the time players can say 'I wasn't at my best in that tournament' but our boys have to be because it is the biggest footballing opportunity of their lives. They have to approach it like that.
"Had I been in their shoes as a player that's how I would have approached it. I would have seen it as the biggest football opportunity of my life.
"You look at past Northern Ireland teams at tournaments and everyone still talks about Gerry Armstrong and his goal against Spain. In this country we have been speaking about the 1982 and 1986 players, who went to World Cups, for the last 30 years. Hopefully 30 years from now we will still be talking about the current players who have been to the 2016 European Championships.
"I want the players to approach it with an excitement and enthusiasm and get every last drop out of the experience and give themselves the best chance possible to do well."
There will be huge disappointment for some of O'Neill's players in May when he names his 23-man squad for the finals, where Northern Ireland will face Poland, Ukraine and world champions Germany in their group.
Last year Ireland's rugby players were informed by email if they had made the cut for the World Cup with those missing out receiving a phone call.
O'Neill's approach will be more personal.
"I'm going to have to leave players out who have possibly been in squads throughout the qualifying campaign. I think the only way to do it is be up front and tell players to their face," he said.
"Our first camp for the players before the finals is for the Football League players coming together on May 16. There will be some players in that camp that may not make it.
"Maybe that first week I will have a discussion with a number of players and tell them they are not guaranteed to go but that they have a week or two weeks to impress.
"I haven't picked my 23-man squad yet. I have in my head a high percentage of that squad but I want the two-week lead in to when I'm announcing the squad on May 28 to mean something and for players to think in that time they can show why they should be in the squad.
"I just don't want to say when players arrive for camp that they aren't going. I want to see what sort of form they are in, what sort of shape they are in, what their fitness is like and also how they are in the group because we will be away a long time. The dynamic of the squad is important as well, such as do players fit in?
"I've also talked about taking four youngsters to France who wouldn't be part of the official squad to supplement the numbers for training but the young players have to be the right type. They have to approach it properly and apply themselves. That's something I have to give a bit of thought to.
"When you have 20 outfield players and you need to sit a player out of training and you want to play 10 v 10 you need an extra body available and ready.
"We want to make sure we have covered every base. Already a lot of work has been done. We have had a couple of analysis meetings and looked at the opposition very closely and will build it up between now and the finals.
"I feel we have a chance of making it through our group and the players believe it too. There's no doubt there are easier groups in the tournament but the main thing is that we believe we can achieve more.
"We are ranked 26th in the world now and when the players go on to the pitch there is a great pride there, their shoulders are back and they are really looking forward to playing international football.
"I think there was probably a time when players dreaded playing for Northern Ireland. They are excited about it now and we want to develop and feed that."
With Northern Ireland undefeated for a record 10 games and the Green and White Army on a never-ending high about heading to France, I ask O'Neill if his team could do what unfancied Greece did in Euro 2004 and lift the trophy.
He laughs out loud at the thought of it before stating that he expects the winner to come from one of the bigger nations.
Reaching the last 16 would be a big enough triumph for O'Neill, who in this newspaper last week declared that his only focus at this moment was on France and that no job would stop him taking the country to the Euro finals, despite speculation linking him with club roles, including the soon to be vacant post at Celtic.
O'Neill, who signed a new four-year contract last month, said: "I don't want to go into the tournament and look back in 10 or 15 years and think I didn't do as well as I could have done because I was distracted. I don't want to have that regret about the tournament. I want to look back and think I did everything possible to try and have a memorable tournament."