Roy Keane has claimed that he was 'too soft' at times during his playing career.
As a player Manchester United legend Keane had a reputation as being an argumentative figure, and frequently clashed with Arsenal's Patrick Vieira.
Keane also received much criticism for a challenge on Manchester City's Alf Inge Haaland in 2001, and the Irishman has proceeded to make some controversial statements as a pundit.
However, Keane says that people 'stabbed him right in his chest' because he was too nice.
Keane told The Irish Independent: 'Sometimes I was too hard. Sometimes I was too soft. If I was critical, looking back on my own career and how I dealt with people, even in management – and people mightn't believe this – but I reckon that sometimes I was too nice to people.
'People stabbed me right in my chest, it wasn't in my back. Because I was too nice to them.'
Keane enjoyed an illustrious career, the majority of which was spent at United, where he won the Champions League, seven league titles and four FA Cups.
The midfielder started out at Cobh Ramblers then moved to Nottingham Forest before signing for United, for whom he frequently excelled prior to ending his career at Celtic.
He said he wouldn't have been able to achieve such success without being fully committed.
'That was who I was. Even pre-season, any game I ever took it easy in, I guarantee you I was the worst player on the park,' he added.
'I couldn't do it. I just couldn't do it. It just wasn't in my make-up. I had to be full pelt. If I lightened up too much in football, I would never have got to England. If I did, I wouldn't have lasted two minutes.'
On Friday, in his role as a pundit for Sky Sports, Keane said that he would have punched David de Gea if he was playing with him after the United goalkeeper's mistake against Tottenham.
Keane said: 'I would be fighting him at half time, I would be swinging punches. This is an established international goalkeeper.'
When he was a player Keane was never afraid to speak his mind. He ended up walking out of the Republic of Ireland's training camp at the 2002 World Cup following a disagreement with manager Mick McCarthy.
In addition, he ended up leaving Manchester United in 2005 after criticising his team-mates on MUTV.