Dutch coach Roel Coumans is one of them.
Best known for his long association with Bert van Marwijk, Coumans spent eight years working alongside the former Netherlands manager, including a spell at Hamburger SV, where he helped oversee the development of young talents who would go on to become established names in European football.
Now, with Hamburg preparing for their second consecutive Bundesliga campaign after successfully preserving their top-flight status following promotion, Coumans has looked back on his time at the Volksparkstadion and reflected on two players he believes always possessed the qualities to reach the very top.
Speaking exclusively to Football Presse, Coumans admitted his spell in Germany remains one of the defining experiences of his coaching career.
"Honestly, amazing," he said. "The club, the stadium, the city, the fans, the pressure you have from the media, the pressure you have from the fans, the pressure you have from the board.
"It's all bringing you to a higher level of enjoying it."
Hamburg were fighting to re-establish themselves among Germany's elite when Coumans and Van Marwijk arrived in 2013, and while results ultimately proved inconsistent, the Dutchman says the atmosphere surrounding one of the Bundesliga's traditional giants left a lasting impression.
"We started very well there. I believe in the first four matches we got eight points, so we brought back the football in a good way. The stadium is always exploding there. That time it was the Bundesliga.
"I'm happy for them that they are back, by the way, because they deserve on the highest level to play."
Hamburg's return to the Bundesliga in 2025 ended a seven-year absence, and after comfortably securing survival in their first season back, the club now enters the new campaign hoping to establish itself once again among Germany's leading sides. For Coumans, however, one of the biggest rewards of his time in Germany came not from results, but from watching young players begin journeys that would eventually take them to Europe's biggest clubs.
Among them was central defender Jonathan Tah.
When Coumans arrived, Tah was still a teenager trying to break into Hamburg's first team. The coach remembers immediately recognising both his potential and the maturity that belied his age.
"When we arrived in Hamburg, Jonathan was just 18 years old, maybe even 17, and he had only just joined the first team. At that time he could not train every day in the morning, so we postponed the training for him to the afternoon.
"He did very well with us already that time. You could see that he had the quality to play in this position even as a young guy."
Experience, Coumans believes, was the only thing missing.
"Of course there was a lack of experience, but he quickly adapted to a high level."
Coumans has continued following Tah's career ever since.
After establishing himself as one of the Bundesliga's outstanding defenders at Bayer Leverkusen, Tah completed a move to Bayern Munich, a transfer Coumans believes was the natural next step.
"I followed him all his career, especially when he was at Leverkusen last year. He did very well and he deserved his transfer to Bayern Munich.
"I believe the club fits him very well."
Coumans believes Tah's influence extends beyond his defensive qualities. Discussing his former player, he described him as a natural leader whose calm authority brings confidence to everyone around him.
"Jonathan Tah is this natural leader. He's not a big talker, but his appearance is already a big step forward to the team.
"He gives balance to the defence line, but he's also capable to be the guard for the people in midfield. As a goalkeeper you can trust him, but also as a defensive midfielder you can trust him.
"Very important for Bayern Munich."
Another player who left a lasting impression was Hakan Çalhanoğlu.
Although the Turkish international has since become one of Europe's most accomplished midfielders, Coumans says the technical gifts were obvious long before the wider football world appreciated them.
"You could see that he was an unbelievable great talent. He used his talent to become an amazing player."
Yet it wasn't only his footballing ability that stood out. Coumans recalls a player whose attitude matched his natural quality.
"A very humble guy.
"Jonathan Tah also, very humble guys, down to earth. They really love the game."
He believes Inter Milan star Çalhanoğlu already possessed every attribute required to succeed at the highest level.
"His technical skill, amazing shot, a good team player, a good vision - everything that a top player needs. I'm very happy that I could work with these two big players."
Alongside Tah and Çalhanoğlu, Coumans also worked with Dutch playmaker Rafael van der Vaart, another footballer he remembers with genuine affection.
"Rafael is first a very amazing person.
"Someone who is really down to earth and also a really good player. His technical skill, his vision, the way he let other people play better, it's from a different level."
Looking back, Coumans sees his Bundesliga experience as far more than another coaching appointment.
Working at one of Germany's biggest clubs, learning under Van Marwijk and helping guide the early careers of players who would later star for Bayern Munich, Inter Milan and their national teams remains a source of immense pride.
"It was an amazing experience for me," he reflected.
"I learned a lot there, especially about the German culture and how to play the physical game."
More than a decade later, as Hamburg continue rebuilding their place among Germany's elite, Coumans can also look back knowing that some of the young players he once coached have gone on to become exactly what he believed they could be.