It's like those scenes you see of an elderly lion who was the alpha in his youth getting pushed out of the pride to die.
Don't waste any of your remaining prime years getbiggers 
Even Mike, though he achieved so much from his teen years, I reckon he regrets getting into drugs and degenerate stuff during his prime age.
He was a great fighter. He really had it all: speed, power, good defense, strength, he could take a good punch. He was on his way to being the GOAT, the way he beat Holmes and Spinks was unthinkable.
His post prison career was a bit of a joke. He took a lot of fights that were pretty safe. Low risk. Some of them looked like outright dives. Seldon and Etienne basically flopped.
As great as he was, he could've been so much better. After Cus died then he fired Kevin Rooney, Don King and his new training team were the worst things to happen to him.