Usually people with impeccable defense like Floyd have it because their chins are suspect, in Floyd's case his chin is really underrated. He's eaten some shots in the past that would have knocked out or knocked down a lot of other fighters. That shyt has to be annoying, you fight this dude, you can't hit him and when you finally land something big he just eats it.
Because he sees all the punches. His ring vision is 2nd to none