Young Boys coach Uli Forte was interviewed in a local newspaper and talked about Walter Mazzarri:

“I had the chance to see him work at Napoli, his silence, his confidence and his aucthority over the group was exceptional. He training session before a game was taken care of by his assistants. Mazzarri himself sat in a corner and smoked whilst he watched the session. At the end, Mazzarri always succeeded in telling the team what they did wrong. His tactical instructions are sensational as well.”

Source: Fcinternews.it