Referee Massimo Busacca's decision to give Arsenal's Robin van Persie a second yellow card for kicking the ball away was the talking point of Barcelona's 3-1 Champions League win at Camp Nou.
Barca were brilliant against Arsenal, but they did enjoy a few decisions going their way. When decisions went against them the players surrounded the referee. With 90,000 fans on his back, too, he was under a lot of pressure.
We definitely influenced referees at Manchester United. We had a presence and reputation as a team and that led to influence. Once, virtually the whole team chased Andy D'Urso after he awarded a penalty to Middlesbrough against us at Old Trafford in 2000.
We would not let it drop for about five minutes. The referee kept backing off and until he was cornered. The photographs the next day showed us with veins popping out of our heads, with club captain Roy Keane leading the charge. The penalty was then saved.
We were wrong, but the referee had been bullied so much in front of 60,000 home fans that I think he would have been scared of giving another decision against us.
Sir Alex Ferguson, the manager, went absolutely mad at us for our behaviour. He's been involved in the odd mind game with referees over the years, but he looked at me and said: "And you were one of the worst."
Referees get a lot of criticism. They have a difficult job, but do not always help themselves and a touch of common sense would often make their jobs easier. Some referees are human, others are like robots who referee for the assessors watching them from the stands and not for the good of the game.
You can have a laugh with some of them and they earn the respect of the players while others become loathed for their patronising ways. Some of them talk to you as if you were a small child.
I did not mind Graham Poll or Uriah Rennie, who were both prominent referees when I played.
You could have a bit of banter with them and I would abuse them for fun, saying: "You're the worst referee I've ever shared a pitch with." They would smile and say: "I can't believe you just missed that chance, I could have scored that. Have you ever thought about looking at your game?"
The vibe was good and I respected them. You can keep a referee on your side that way. I could not stand Mike Dean, who awarded a controversial penalty to Chelsea at Blackpool on Monday. You watch him referee and he is like a dictator.
David Elleray was the same, you always felt that you were walking on a tightrope with them around.
They thought they were on a power trip and would order me to "Come here now!" like I was a little boy.
Dean once sent me off for Fulham at West Bromwich Albion. In fairness to him, I had started a 22-man brawl. Neil Clement had fouled my teammate Louis Boa Morte and I knew Clement was going to be sent off.
I did not like Clement, so I went up to him smiling and said: "Off you go." He hit out at me and tried to butt me so I punched him twice.
I knew I was going to get sent off for the one punch, so I took another free shot, which connected.
I then asked him if he wanted to carry on the fight in the tunnel, but he did not fancy it and was nowhere to be seen there. I was banned for four games, charged with violent conduct and abusing a match official. There was a £10,000 (Dh59,200) fine, too. Not my finest hour.
Sometimes players pay no attention to referees. Keane ruptured a cruciate ligament in a clash with Alf Inge Haaland at Leeds United in 1997. Haaland stood over Roy mocking him and telling him that he was faking injury.
Roy never forgot that and four years later took revenge on Haaland, who was then playing for Manchester City. Roy took him out with a horrendous tackle above his right knee for which he knew he would be sent off. That was a price worth paying for Keane.
Other decisions are less clear cut. I have no doubt that referees talk about players because players talked about referees.
Nani is probably a player who has a reputation for making the most of a challenge - and he suffered from that last week when he was victim of a Jamie Carragher tackle which should have been a red card.
It was a mistake by the referee, but mistakes happen. Some people believe refereeing standards have deteriorated - but in my experience, they are pretty much the same as they have always been.