The mercurial forward represented the likes of Real Madrid, Milan and Inter but was dogged by poor discipline, and admitted his slothfulness did not help him
Cassano consistently struggled to prove his quality during spells at Real Madrid, AC Milan and Inter in a career fraught with ill-discipline and fitness issues.
After failing to take his chances at such prestigious clubs, the 33-year-old is enjoying a return to form at Sampdoria under Vincenzo Montella this season.
The forward says he does not rue the impact his past behaviour had on his career and wants to see out his playing days at the Genoa club.
"Let's say I ruined it for myself. I've always been a layabout - I've never done anything to help me produce my best," Cassano said on Mediaset.
"But I'm okay with that. I'm happy. I love it here in Genoa and I want to end my career with Sampdoria."
The 33-year-old hopes to put together a series of strong displays to end the season and earn himself a place in Antonio Conte's Italy squad for Euro 2016, though he feels his chances are slim.
"It's a one in a billion chance but I want to give it a go because Conte doesn't shut the door to anyone," Cassano added.
"My attitude has changed in training too. I want to try but if I don't make it I'll cheer Italy on at the Euros from the outside."