Sport, at any level, takes passion: and in the highest echelons, players leave blood, sweat and tears on the pitch. Given that playing for your country is something all young athletes dream of, it's no surprise so many wear their hearts on their sleeves out on the field.
Given the amount of will and fire it takes to be the best, of course tensions boil over from time to time –even among teammates.
At the end of last year, Springbok Bismarck du Plessis got into a messy brawl with his Montpellier club teammates. On Saturday, the Sharks' stars involvement in another volatile encounter with a teammate made him one of five players we think are worth a tutting for teammate tussles...
1. Bismarck du Plessis vs Mohamed Haouas – Montpellier (Rugby)
French Top 14 Rugby log leaders Montpellier made light work of their nearest rivals Racing 92 with a dominant 41-3 victory on Saturday, but it was Du Plessis' shenanigans that stole all the headlines.
Bismarck du Plessis just having a fight with his Montpellier team-mate in the warm-up. pic.twitter.com/z3Ma0RHtAg— Ben Coles (@bencoles_) March 10, 2018
The match got off to a tense start, after a fistfight (during the warmup!) between Du Plessis and fellow Montpellier player Mohamed Haouas. Teammates got between the two as they traded blows, calming things down.
If the fight was Montpellier's way of showing Racing 92 what its forward attack is all about, the visitors were suitably intimidated, and subsequently streamrollered.
2. Benoit Assou-Ekotto vs Benjamin Moukandjo – Cameroon (Football)
In the biggest football tournament in the world, the 2014 Fifa World Cup, Cameroon teammates Benoit Assou-Ekotto and Benjamin Moukandjo did not read the "unity is strength" script. Cameroon's less-than-memorable 2014 campaign went from bad to worse, culminating in the pair's on-field fight.
Assou-Ekotto headbutted his own Moukandjo in the final minutes of their dead-rubber loss to Croatia;an ending that summarised their horrible 2014 tournament.
3. Mario Balotelli vs coach Roberto Mancini – Manchester City (Football)
One of football's most infamous players, Mario Balotelli, has been involved in plenty of on-field battles with the opposition. But he took aggro to new heights in his bust-up with his own coach at the time, Roberto Mancini.
The English press made much of the rumours that Mancini had lost it in the dressing room, but eventually Balotelli would get his act back together. Once it was all patched up, he inspired Manchester City to an unprecedented Premier League title over rivals Manchester United.
4. Michael Jordan vs Steve Kerr – Chicago Bulls (Basketball)
Arguably basketball's best modern-day player, Michael Jordan was hailed as the best on the court, and his team, the Chicago Bulls, won two three-peats (winning the NBA championship three times in a row) between 1991 and 1998.
Steve Kerr, now the coach of the Golden State Warriors, was a great shooter during his time at Chicago Bulls, but the two players could not stand each other.
According to Bleacher Report, Jordan was also the king of trash talking, and he had some harsh words for Kerr during one practice. Kerr gave back tit-for-tat, and it escalated to fisticuffs.
Jordan swung first, punching Kerr in the face, but Kerr held his own in the subsequent slugging. The altercation actually brought the two closer, and they went on to win a few titles together.
5. Lee Bowyer vs Kieron Dyer – Newcastle United (Football)
Trailing 3-0 at home to Aston Villa in 2005, then-Newcastle player Lee Bowyer – always one with a tendency to go a bit ape – was not in the mood for verbals.
When teammate Kieron Dyer told Bowyer he wasn't passing to him because Bowyer was playing "like sh*t", Bowyer flipped out. The two had an on-field fist-fight that saw both men sent off. No, it didn't improve the 3-0 score at all.