When Kieran Tierney settles into life in the Premier League with its riches and its glamour and its global appeal, it would be easy to assume that his life's ambition had been met. Easy but wrong.
Of course Tierney wants to test himself against the best. Of course he wants to go up against the behemoths, the Mo Salahs, the Sergio Agueros, the Harry Kanes, and with that profile comes wealth on a scale that would have been unimaginable to him even a few years ago. A rumoured weekly salary of £75,000 at Arsenal makes an annual wage of almost £4m not counting bonuses. For a young man who lives quietly and modestly, this is utterly life changing.
Not that he was desperate for his life to change. He was happy with his life. His life was exactly the type of life he dreamed of as a kid. Back in those days, Tierney couldn't see, and had no interest in seeing, a football world outside the east end of Glasgow.
He said he always hassled his dad to let him hang around after games so that he could collect autographs he had probably already collected multiple times. "I know what it's like to be out there," he said of his young self, a child in thrall to Celtic. "When you're younger some people dream about playing in the English Premier League but I only dreamed about playing for Celtic. It was always a Celtic strip I wore."
Some may say that Tierney is now entering a better world, a place where his new winger, Nicolas Pepe, was recruited for £72m, where his two new strikers, Pierre-Emerick Aubameyang and Alexandre Lacazette, were brought in for £56m and £46m, where multi-million pound players can sit on the bench or in the stand, largely forgotten, where television revenue is knocking on for £140m a season, where the wage bill is £240m a season, where the turnover is £403m a season.
Tierney might dispute that it's better at Arsenal. The word he might use instead is different. For as long as he lives, and no matter what glory he achieves in London, it's hard to envisage him saying anything is better than what he had at Celtic.
'An animal and a freak'
That's where the sadness comes for the supporters at Parkhead. They always knew that this day was coming. Tierney was never in a rush to leave but his talent was too big to be housed in Scotland for the rest of his days.
His departure comes with the soothing balm of that £25m transfer fee and a chunky portion of whatever sell-on fee might accrue down the line, but this was one of their own and it must be especially difficult for them to see him go even though they would have been steeled to its inevitability. Virgil van Dijk went, Victor Wanyama went, Moussa Dembele went. A brilliant spine went, but a bit of heart goes with Tierney.
You have to go back a long time to find a homegrown Celtic player that meant as much to them. They watched him come through the ranks, a tall and skinny youngster with an appetite for the game that was scary. Brendan Rodgers called him an animal. Callum McGregor called him a freak.
His back story is all Celtic. Famously, he was a ball boy on the night they beat Barcelona in the Champions League in 2012. He made his debut at 17 in a pre-season friendly against Tottenham in Helsinki. Celtic lost 6-1, but Tierney said in the aftermath that everything he had ever wished for in life had just come true.
He was the boy who got elbowed in the mouth in his first Scottish Cup final in 2017, who was taken to hospital and who then, in a madcap dash back to Hampden, sprinted into the stadium still in his kit to be part of the trophy presentation. He was Celtic's youngest ever captain. He was the guy whose standards very rarely dropped.
In tough times, he stood up. There are many, many images of Tierney thundering down the left flank as if his life depended on it, but one night stands out. It wasn't even a memorable night, not in a good way at any rate. Celtic were playing Molde in the Europa League. It was November 2015. Ronny Deila was the manager.
Celtic lost 2-1 at home. Parkhead seethed. Their ire flew right and centre, but not left. Tierney was 18 and he was by a million miles their best player. Not just in terms of the quality of his work but the unmistakeable, lung-busting effort he was putting in. As several voices in the crowd said that night, a kid was showing them all up.
'Both clubs have done well'
Unai Emery's pursuit of Tierney was drawn out, but that was always going to be the case because Celtic were never going to weaken, not in this transfer deal above all transfer deals. Peter Lawwell, the chief executive, knew that he couldn't keep his player but he also knew that he wasn't letting him depart for a shilling less than his value.
Both clubs have done well. A big fee on one side, a big player on the other. Celtic won't find another Tierney any time soon, but they have serious money to play with at least.
Tierney's move adds to the growing number of Scots in the Premier League's upper echelons. Andy Robertson at Liverpool, Scott McTominay at Manchester United, Ryan Fraser at Bournemouth. There was talk of John McGinn and Old Trafford before he committed to a new deal at Aston Villa. Even if that chat was fanciful you can see how the midfielder might be the subject of interest from a heavy hitter if he brings his coruscating Championship form into the top level.
Oli McBurnie, a £20m player, is in that league now, along with Kenny McLean and John Fleck. So, too, Stuart Armstrong and Robert Snodgrass. There are others. It's been an age since so many Scots operated at that level. Things are turning. This is the most exciting group of players in a generation.
Arsenal have invested heavily in their new left-back. It would be a major surprise if they ever have cause to regret it. They're getting talent, but that's a given. What they're also getting is honesty and hard work and the kind of commitment that their fans will recognise and acknowledge in a heartbeat.
Once he gets over his injury, and he's said to be close, Tierney only has to do one thing in London: be himself.