Football fans, players, coaches, owners... whoever, do not take losing well.
In some instances people will go as far as inventing theories, some of them completely crazy, as an excuse as to why. It can be the only explanation! That's when you have yourself a conspiracy.
Here's a look at seven of the most far-fetched theories to have emerged over the years.
The 1974 Oranje Pool Party
'Cruyff, champagne and naked girls' was the headline that German tabloid Bild ran the day before the 1974 World Cup final between West Germany and the Netherlands. The story was plastered on the front page and is believed to have conspired to throw the Dutch off their game.
No one denied the pool party happened, but in reality it had occurred several days earlier and many blame Bild for deliberately waiting until the day before the final to print the 'details'.
As for Johan Cruyff, he wasn't even actually present. He spent much of the night before the final on the phone with his raging wife, as apparently did many of the other Dutch players, and was just a shadow of his usual self on the pitch as West Germany prevailed 2-1.
Brazil Were 'Spiked' by Argentina
The South American rivalry between Brazil and Argentina took on even more meaning at the 1990 World Cup when Brazilian defender Branco accused the Argentines of going as far drugging him with tranquilizers during a second round game between the countries.
Branco took a sip from a water bottle supplied by Argentine team physio Miguel di Lorenzo and claimed it had been spiked. Argentina won the game by a single goal, scored after the incident, against the run of play and went all the way to the final.
Two days had passed when Branco declared he had felt unwell and dizzy from drinking the water. The case then gained renewed traction in 2005 when Argentina coach from the time Carlos Bilardo sensationally commented, "I'm not saying it didn't happen."
'They Are Never Going to Let a British Team Win the European Cup'
Before Celtic and Manchester United won the European Cup in successive years in the late 1960s, there were at least a few people who believed the competition was fixed so that a British club could never lift the coveted trophy.
The original claim came from a Liverpool director in 1965 when his team were beaten 3-0 by Inter, partially thanks to two controversial Italian goals and one wrongly disallowed for Liverpool.
There was certainly enough to build a conspiracy from. The Football League in England had originally opposed the European Cup when it was created in 1955, even banning then champions Chelsea from competing in the inaugural season. Was this UEFA taking its revenge? Well, no, obviously.
Barcelona Got Special Treatment Because of UNICEF
Bitter after seeing his Real Madrid side knocked out of the Champions League in 2011 by fierce personal rival Pep Guardiola, Jose Mourinho was responsible for starting the rumour that Barcelona received special treatment because of their partnership with UNICEF.
Barça displayed the charity's name on their shirts free of charge at the time, and Mourinho seemed to hint they were being viewed too favourably because of it. Either that or UEFA was secretly ensuring their continued success at the expense of others, he claimed.
"I don't know if it's the advertising for UNICEF," Jose said at the time. "I don't know if it's UEFA. Congratulations for a wonderful football team. It must be difficult to get this power. They have managed to get this power. No one else has any chance really."
Howard Webb was a Manchester United Fan
Fans of other Premier League teams often moaned when renowned referee Howard Webb was put in charge of Manchester United games because they believed he always gave Sir Alex Ferguson's team a helping hand with questionable decisions in their favour.
Doctored images of Webb in United shirts made popular meme topics over the years.
The former policeman always denied it, of course, but he did quip in 2015 that United hadn't been the same team since he retired. Many saw it as the joke it was, but others raged.
Arsenal Poisoned Tottenham to Beat Rivals to Champions League
Tottenham were on course to qualify for the Champions League for the first time in 2005/06, as well as finish above local rivals Arsenal for the first time in more than a decade. All they needed to do was match whatever the Gunners did on the final days of the season.
A game against a West Ham side with nothing left to play for should have been manageable, but disaster struck the night before. Staying in a hotel in Canary Wharf, a number of key players became violently ill after eating what was identified as dodgy lasagne.
Michael Carrick, Robbie Keane, Edgar Davids, Michael Dawson, Aaron Lennon and Teemu Tainio were among them, ripping out the core of the team. The Premier League rejected a request to postpone, and conspiracy theorists pointed the finger at some kind of sabotage effort from Arsenal, who of course had benefited when Spurs lost against the Hammers.
Nike Forced Ronaldo to Play the 1998 World Cup Final
Brazilian phenomenon Ronaldo was global football's biggest superstar at the 1998 World Cup. He had become the most expensive player in history a year earlier and it was his tournament.
Everything was going to plan as well. Brazil reached the final where they were due to face host nation France, but when the Selecao submitted their team-sheet, Ronaldo wasn't on it.
The planet was stunned, but then Brazil submitted a second team-sheet with him. He had suffered a fit in the hours before the game, but then insisted he was fine. Ronaldo clearly wasn't fine, though, and some still insist that Nike, who had invested so much money in him and the Brazilian team, forced him to play - something he has always denied.