It’s not a trophy or his bursting medal collection or even that he’s playing for a team which has dominated the English game over the last two seasons.
Though that helps, of course.
As spectators we know football can ignite a special feeling within.
A feeling that, when things go right, is hard to replicate.
It’s that, a sense of complete enjoyment, which Gundogan cherishes so much from his time at City and one, having committed his future to the Club, he hopes remains.
“Getting 198 points in two Premier League seasons is amazing,” he said after signing a contract which keeps him at the Etihad Stadium until 2023.
“It’s not just that, but also the way we play. We are so dominant and so enjoyable for spectators to watch.
“For me it’s not always about winning trophies.
“Of course, that is a part of football but it’s also about the feeling you have on the pitch.
“Not just in the games, but in a training session maybe, to have moments where you feel like ‘this is so much fun to be here on this pitch with these guys.’
“I had it quite often over the last couple of years and hopefully I can enjoy it even more over the next period.”
That said, it’s impossible to disconnect trophies from the German’s City career.
He’s won seven, a haul made sweeter by the fact he bounced back from a season-ending knee injury in his debut campaign to make a telling contribution to the success that followed.
There’s more of that to come he feels and at 28, an age many players would consider to be your peak, he says City’s potential was an important factor in his decision to remain in Manchester.
“When I joined the Club I had amazing talks with Pep.
“It was always an achievement to play for him and to be able to continue for at least four more years is an amazing feeling.
“That was the main thing. We have great players and have already achieved a lot, but I think there is more to come.
“We have a lot of potential. I am happy that I can be a part of trying to get that out of us.”
Talk of delivering on promise understandably brings the one trophy which eludes this group of players looming into view.
The Champions League, which Gundogan came close to winning in 2013, when he scored a penalty in Borussia Dortmund’s 2-1 defeat to Bayern Munich.
It’s a loss he wants to avenge with City.
“It’s something that I definitely want to win one day,” he added. "But I try not to think about it too much.
“Once the competition starts you go game by game. It’s a long and very tough way, the past shows that.
“It is possible, especially with the potential and the qualities we have in the squad.
“As a club we should try to target it. Anything else would be a mistake.”