Inter Milan forward Antonio Cassano has admitted that he has failed to live up to his potential since bursting onto the scene as a youngster with Bari in 1999.
The 30-year-old is renowned for his fiery temper, and has been involved in a number of controversial incidents during his 14 years in the game.
The Italian international, whose illustrious list of former clubs include Roma, Real Madrid and AC Milan, conceded that he has not always conducted himself as a professional.
"It's my fault if I haven't had a better career," Cassano told Italia 1. "I thought that quality alone was enough to take you forward.
"I've played for great clubs, but I've always done little. I've only done 50% of what I could have done, I've always found a way to not train in a professional manner.
"I would say that I was in the wrong 99% of the time. However, I was put into a position to make mistakes. I went from being right to wrong in an instant."
Cassano's future at the San Siro is under scrutiny after his latest falling-out with coach Andrea Stramaccioni.