I'm also somewhat bothered with Michael's Al in Part III as is already mentioned.

But some people can change significantly. A good example is George Foreman, the boxer.

Before he fought Muhammad Ali he looked like an arrogant and nonchalant toughguy.

But after he was beat up by Ali he wasn't the same man. Years later, when he made a comeback, I almost didn't recognise him anymore as he seemed to have changed in a (somewhat insecure) but sympathetic guy.