The Portuguese made the revelation while discussing his relationship with the United boss, who he says fills the squad with confidence.
Fernandes told TV2: "He has his moments, like everyone else. I think he's been really mad at me twice.
"It's not so much, I've played 54 games now. During those fights he has been angry with me twice, it's not bad, so I'm happy with that. Sometimes he has to be calm, other times he has to scream and yell at his players.
"It's about how to get the best out of the players. For me, it works well that he is angry sometimes. I don't want to be a player no one demands anything of."
Fernandes added: "I think everyone knows that he gives the players a lot of confidence. The conversations we had when I came here were very important to me, because he always said that I should express myself.
"In the beginning, he often repeated that I should express myself, be myself and do the same as I have always done. Over time, he has begun to demand more and more of me, and I think it is important that I demand a lot back."