Former Borussia Dortmund physio Frank Zollner admits it was a rollercoaster working with Liverpool manager Jurgen Klopp.
Zollner concedes he sometimes would think Klopp was "selfish".
He explained to Goal: "He's a special guy. So many times you thought: 'Incredible guy', but sometimes you could also think 'How selfish!'.
"Once I got a call from Jakub Blaszczykowski who was on his way back from the (Polish) national team. He said he couldn't train because of a muscle injury, but would still show up at the team meeting.
"Before the meeting I went to Klopp with 'Kuba' (Blaszczykowski) and explained how it was. Then he got really mad, probably because he just found out about Kuba's injury.
"Zeljko Buvac (Klopp's former assistant coach) would often show up in such situations and say: 'Kloppo, smoke a cigarette and calm yourself down'.
"He was one of the best assistant coaches I had ever worked with. But Kloppo had the b***s to apologise when he had crossed the line."
Zollner is now active with VfL Bochum in the German Second Division.