I saw an interview of Dacourt on french telly about him. He played with him back in Everton and now in Inter.
Dacourt said that Materazzi is a very gentle men off the pitch. He called him a cream of a guy. And a very good father.
On the field, he continued, he's just very motivated to win.
Dacourt clearly didn't want to criticize his new teammate, but I do believe for the off the pitch part