The Italian, who coached his compatriot first at Roma and then at Real Madrid, was speaking following the striker's training ground bust-up with Inter coach Andrea Stramaccioni last week.
"It's a shame," Capello told Radio Rai. "He could have done a lot more in his career than he has. I hoped that he would mature after the birth of his son, but, unfortunately, it is the same old story.
"He's a good kid, generous, but he doesn't understand that there are limits and when he lets loose there is no stopping him. He doesn't know the boundaries when it comes to respect. This has influenced his career.
"He only sees football in his own way. That inevitably sees teammates sometimes lose respect for him. He needs to understand that, at certain times, he has to accept the decisions of others."
Cassano was left out of the Inter squad for their 3-2 comeback victory over Catania away from home in Serie A on Sunday.