Liverpool boss Jurgen Klopp admits he's not one to work with maverick players.
Klopp was interviewed by BT Sport about his 'non-negotiables' as a manager.
The German, 55, highlighted how important discipline is when managing players.
He revealed: "I'm very disciplined. I'm very relaxed, but sometimes things happen - not really bad things - and I ask 'do we have a fine for that?'
"And then they tell me 'no, we don't have a fine for that because it's never happened before'.
"Discipline is very important to me, but the players are used to that - they grew up in the football environment and you can't do team sport without discipline.
"It's better not to sign really 'difficult' players.
"And if somebody develops into a 'difficult' player, you better bring him out of the building because they might help you in the short term but will always hurt you in the long term.
"So we never really have disciplinary issues."
Klopp added: "There have been players who didn't fit with my principles, and that's when we parted ways.
"I've never signed a player like this, but from time to time there have been.
"But in 22 years as a manager it's not even a handful, so I think that's a pretty good number."