Nosebleeds are an unwanted wrinkle in life that are annoying but, for the most part, do little lasting damage.
However, something as simple and innocuous as a few bloody noses would prove to be one of the decisive factors in Marc-André ter Stegen's footballing career.
When Ter Stegen's grandfather signed his grandson up to Borussia Mönchengladbach - his hometown club - as a four-year-old, he wasn't a goalkeeper. By the age of ten, Ter Stegen was still playing as a striker when his youth team coach presented him with a hefty ultimatum: go in goal or leave the team.
The side's previous number one - bizarrely - suffered from regular nosebleeds and Ter Stegen's running style did little to help the coach envisage a career for the child as an outfield player. Fortunately, Ter Stegen rapidly thrived in the role, flying through the youth ranks until his chance with the senior side came in 2011.
As Gladbach toiled at the bottom of the Bundesliga, the incoming manager Lucien Favre turned to his 18-year-old reserve keeper. In a local derby against fierce rivals FC Köln, Ter Stegen pulled off a string of saves as his side ran out 5-1 winners on their way to a dramatic relegation survival.
From that debut, the die-hard Gladbach fan who happened to be wearing a goalkeeping kit missed just one game for the first-team over the next three seasons.
Rumours emerged that the La Liga giants had been pursuing Ter Stegen for over a year after the club's former first-choice Víctor Valdés announced he would not be renewing his contract. The Germany international denied the notion that he'd signed a pre-agreement with the Catalans in 2013 but it's easy to see why Barcelona were keen to snap him up, given his ease with the ball at his feet.
In his third season in Spain, before a Champions League visit to his old club Gladbach, Ter Stegen delivered the telling line: "Sorry if my way of playing makes you nervous, but that’s how I play." Since his days as a youngster up front, Ter Stegen has been keen to hone his ball skills.
As he told The Telegraph: "I always wanted to play with both feet, so today I’m happy I trained it so often.”
Ter Stegen explained how this comfort in possession is crucial for today's goalkeepers, especially at Barcelona: “The game has changed a lot during the last years, now the goalkeeper is very important, he needs to be confident with his feet. That’s very important at Barça, it has been for a very long time and they were searching for someone who is happy to play with his feet.”
The revolutionary former Barcelona player and manager Johan Cruyff had an influence (and strong opinion) on numerous aspects of the modern game - even goalkeeping. For Cruyff, goalkeeping was not simply about diving around and saving shots, it was 'a question of vision'. Ter Stegen - the only goalkeeper with two assists in Europe's top five leagues this season - wonderfully embodies that particular ideal.
In fact, this campaign has seen Ter Stegen devote an even greater focus on his footwork. Barça's number one tops the La Liga standings (by quite some margin) for the number of passes made by a goalkeeper and - on average - completes the shortest passes and takes the shortest goal kicks.
Quique Setién's reign as Barcelona manager may have seen them relinquish the La Liga title to Real Madrid, but the self-confessed Cruyff disciple has given Ter Stegen even more responsibility with the ball at his feet.
The starkest example of this came against the high-pressing Getafe in February. On several occasions, one of Barcelona's centre backs would roll a short goal kick to Ter Stegen. Getafe's players seemed unsure whether to close down the goalkeeper, so hovered on the edge of the penalty area as Ter Stegen mulled over his options in a nervy game of cat and mouse.
Barcelona would ultimately prevail 2-1 - and their opening goal was the result of a slick 15-pass move - as Ter Stegen made more passes than Getafe's midfield combined.
Cruyff once opined: "Football is a game of mistakes. Whoever makes the fewest mistakes wins." Ter Stegen's confidence in possession can sometimes lead to the odd (or often spectacular) error.
This is an aspect of a ball-playing keeper's game which is near impossible to eliminate but can be reduced, as Ter Stegen explained: "I tried to take fewer risks, or at least more calculated risks. This is the key word for me, it’s always calculated, I know exactly what I’m doing."
Ter Stegen may have spent more than half his life learning and playing football west of the Rhine, but this calculating, wonderfully skilful risk-taker is perfectly moulded to the deep-rooted footballing ideals of Barcelona.
And to think, he could just as easily have been a middling striker with a funny run had it not been for a few nosebleeds.