All players and fans understand that each Premier League club has a designated player to take penalty kicks. It goes without saying that it is the one who is most reliable and at Chelsea that is definitely Cole Palmer who has a great record from the spot.
That is what made it all the more astonishing on Tuesday night at Stamford Bridge when there was an unseemly squabble over who should take the penalty after Cole had been fouled in the area. Chief protagonists were Nicolas Jackson and Noni Madueke who did themselves no favours quarrelling like kids on the playground.
Eventually captain Conor Gallagher sorted things out and Cole duly obliged from the spot for the ninth time this season.
However, the incident marred what had been Chelsea's most entertaining display of the season as they romped to a 6-0 victory over struggling Everton. This was thanks to an extraordinary display by Cole who banged in four goals, to make it 20 for the season.
The unnecessary bickering over the penalty does reflect the feeling of many fans that all is not well in the Stamford Bridge dressing room. Some Chelsea stars are perceived as playing more for themselves rather than the team. Surely they cannot be jealous of Cole because without him Chelsea would be near the relegation zone.
Chelsea manager Mauricio Pochettino was not impressed by the antics of Jackson and Madueke. "I can't accept this kind of behaviour," he said. "We need to change and think in a collective way."
Everton fans may recall a similar incident at Goodison Park involving Belgian star Kevin Mirallas in January 2015 in a match between the Toffees and West Bromwich Albion. With the score 0-0 just before half-time Everton were awarded a penalty. Although Leighton Baines was the regular penalty taker Mirallas grabbed the ball and despite the objections of teammates insisted on taking the kick.
When Mirallas missed the penalty it is safe to say he was not the most popular player at Goodison and it came as no surprise when he did not appear in the second half. Everton manager Roberto Martinez explained the Belgian had a "hamstring situation" although few believed that.
As the Independent newspaper neatly put it: "Mirallas wanted the glory. What he got was an early bath."
Teammates fighting among themselves is nothing new of course and sometimes it develops into actual punch-ups rather than the petty pushing and shoving witnessed at Stamford Bridge.
In 1979 for the first time in the Football league two players from the same team were sent off for fighting one another. Charlton's Derek Hales and Mike Flanagan both received red cards after coming to blows in a Cup match against Maidstone. Apparently Hales blamed Flanagan for a poor pass and Flanagan replied with some industrial language and the two started fighting.
The most high-profile incident occurred in April 2005 in the closing minutes of a Premier League match between Newcastle and Aston Villa. A brawl erupted between Newcastle teammates Kieron Dyer and Lee Bowyer who had to be separated by players from both sides. In addition to red cards, Dyer suffered a three-match ban while Bowyer's was increased to seven as he was adjudged to have thrown the first punch. Bowyer was said to be upset because he believed Dyer was deliberately not passing the ball to him.
There is so much pressure in modern football that it is inevitable players will squabble with one another and a bit of name-calling is to be expected. But coming to blows is not helpful at all.