Footballers can often be superstitious about the number they wear on their back.
It should be the furthest thing from their mind when they take to the pitch, and yet it's a far bigger deal for some, as we have seen from recent examples at Manchester United in particular.
When Antonio Valencia switched to the fabled #7 shirt at Old Trafford, he soon switched back to #25 having had the worst spell of his United career under the weight of expectation that the jersey carried, and Memphis Depay too left having been unable to perform in the shadows of those who made it legendary before him. Even Anthony Martial was believed to be upset when Zlatan Ibrahimovic was handed his #9 shirt and the Frenchman was given #11.
It's a big deal for some, but not Michael Carrick.
In a recent interview with Paul Merson for the Fantasy Football Club, Carrick opted against the usual 'Teammates XI' and instead chose to pick an XI of the best opponents he ever faced and never played with. The current Manchester United #16 named Roy Keane in the CDM role.
Before he would express his belief that Keane's passing was criminally underrated, he explained why he was never bothered by people drawing comparisons between him and the Cork man after taking over the #16 shirt.
Do you know what, it never really bothered me that much.
There was a lot of talk about it, people saying about the pressure and having to.. I was never Roy Keane. I'm not that type of player. I'm just not that style, so I was never going to be.
Say when I finish at United, and they buy somebody else, they're not going to be me, they're going to be whoever they are.
But, what a player. Just relentless. Do you know what he was so good at but never gets credit for? Playing it into the forward's feet. His passing was different class.
People say about his forward runs, and he's aggressive, his tackling, and a leader in general, but technically he was top drawer and that gets overlooked at times.
We've heard that before from those who knew Roy's game best, his passing is something that doesn't get talked about enough in comparison to the other attributes he was known for.
None of that mental pressure impacting Carrick's game anyway, that's for sure.
The 'Opponents XI' he went on to name was a thing of beauty as well;
Peter Schemichel; Phillip Lahm, Jaap Stam, Paulo Maldini; Roy Keane, Andres Iniesta, Xavi, Clarence Seedorf; Thierry Henry, Didier Drogba, Lionel Messi.