Opinion: 'Muhammad Ali' documentary doesn't shy away from boxer's flaws

Barely a minute into the documentary “Muhammad Ali,” the tone is evident but doesn’t foreshadow what’s coming next.

A lighthearted, playful moment as he steals corn flakes from one of his daughters. Jubilant crowds chanting his name. And of course, the brash, braggadocio style of talking (and fighting) that athletes of his generation wouldn’t dare emulate -- or didn’t have the personality or gall to pull off.

“Boo, yell, scream, throw peanuts, but whatever you do, pay to get in,” Ali proclaims at the height of his boxing prowess. (The documentary uses his given name, Cassius Clay, up to the point where he changes it to Muhammad Ali in 1964.)