Sir Alex Ferguson has never been afraid to speak his mind or worry about the consequences.
As a result, he has come into conflict with fellow managers, players, match officials and the authorities over the years.
Here we look at some of his most famous bust-ups.
Having famously set out his stall to knock Liverpool off their perch, Ferguson had - and still has - an interesting relationship with their former manager Benitez. It was the Scot who prompted the Spaniard's "facts" rant in January 2009, claiming he was nervous because the Reds were leading the race for the Premier League title. "I was surprised by what has been said, but maybe they are nervous because we are at the top of the table," Benitez said. United ultimately won the league, finishing four points ahead of the Merseysiders.
Frenchman Wenger and Ferguson were involved in a series of spats as Arsenal threatened to break United's stranglehold on English football. The war of words came to a head in the famous 'Pizzagate' incident in October 2004 in which, after the Red Devils ended the Gunners' 49-game unbeaten Premier League run at Old Trafford, Ferguson took a slice of pizza full in the face. The Scot's comments on his French counterpart over the years have included, "He's a novice. He should keep his opinions to Japanese football", while Wenger once insisted he would "never speak about that man again". There has, however, been a thaw since, perhaps as a result of the decreased threat posed by the north London club.
The rivalry between Ferguson and Dalglish dates back to their Old Firm days in Glasgow, although the former Celtic man has proved a redoubtable opponent when it comes to verbal jousting. The older man reportedly told friends after one on-field encounter with the future superstar or Scottish football, "That plump wee Dalglish boy won't make a player", and later suggested his Blackburn side did not have the "bottle" to win the Premier League. He was wrong on both counts. Dalglish has had his moments too, and after overhearing a Ferguson rant in the wake of a 3-3 draw at Liverpool, he told reporters: "You'll get more sense out of my baby than him."
Newcastle boss Pardew got both barrels in December last year after expressing his surprise that Ferguson had not been punished for a furious broadside aimed at referee Mike Dean at half-time in United's 4-3 league win over the Magpies. The United manager, who had disputed the visitors' second goal, said: "The press have had a field day. The only person they have not spoken to is Barack Obama because he is busy. It is unfortunate, but I am the manager of the most famous club in the world - not Newcastle, a wee club in the north-east."
Beckham was left with a reminder of his brush with Ferguson after being caught just above the eye by a boot allegedly sent flying by the enraged manager in the wake of a 2-0 FA Cup fifth-round defeat by Arsenal in February 2003. "It was a freakish incident. If I tried it 100 or a million times it couldn't happen again. If I could I would have carried on playing!" the Scot said later.
Holland defender Stam was dealt with summarily after revelations in his autobiography cast Ferguson in a poor light. Stam claimed, among other things, he had been poached by United and that the manager had ordered his players to dive in European matches. He was sold to Lazio weeks later.
Referee Wiley found himself in the firing line after Anton Ferdinand's last-gasp own goal had rescued a 2-2 draw for United against Sunderland at Old Trafford in October 2009. He said: "The pace of the game demanded a referee who was fit. He was not fit. It is an indictment of our game. You see referees abroad who are as fit as butcher's dogs. We have some who are fit. He wasn't fit. He was taking 30 seconds to book a player. He was needing a rest. It was ridiculous." Ferguson later apologised, but received a four-game touchline ban and a £20,000 fine.
Ferguson landed himself a five-game ban and a £30,000 fine after lashing out at Atkinson in the wake of a 2-1 league defeat at Chelsea in March 2011. Ferguson landed an improper conduct charge after remarking: "You want a fair referee - or a strong referee, anyway - and we didn't get that. When I saw who the referee was, I did fear it. I feared the worst."
The FA itself was the target of a Ferguson rant in April 2004 after midfielder Paul Scholes was charged with violent conduct after referee Paul Durkin failed to spot his clash with Middlesbrough's Doriva. He said "There is a scenario for every club in the country and another one for us. We expect Paul to have a difficult hearing. Put it this way - I don't think he will get the same hearing as other players get."
Ferguson was dismissive of Premier League chief executive Richard Scudamore's efforts to bring a new respect into top-flight football. Asked to comment on the 2011 initiative, Ferguson replied: "Richard Scudamore doesn't have a lot to do. He is trying to elevate the Premier League. That is his job. But I feel he is jumping off a high diving board here without thinking about it."