By Nick Georgandis

Serena Williams is a _________________!

Most people have a answer to the above mad lib. Very few of them have the same answer.
Reading several articles about Muhammad Ali turning 70 on Tuesday had Williams on the brain several times throughout Tuesday night's sessions Down Under.

LIke Ali, Williams has become a polarizing figure in her sport. Like Ali, she's African-American. Like Ali, she's opinionated, and the more questions you ask her, the more she'll give her two cents.

It's been more than 30 years since Ali last appeared in the ring, and in that span of three decades he's become a revered sports legend  - respected for his battle with Parkinson's disease, revered when he lit the torch at the 1996 Summer Olympics in Atlanta and magnamious in his humanitarian efforts, which are so great that he was awarded the Presidential Medal of Freedom in 2005, the highest award a civillain can receive in the United States.

But prior to all that, Ali was a braggart, sometimes a bully, and always looking to entertain, be it himself or a large audience. His social life was the stuff of much gossip. He delved in other fields and he always seemed to invite controversy.

Sound like anyone you know?

Serena Williams is at times inexplicable, at times petulant and at times absolutely brilliant.
In the last 18 months, her popularity has dipped to an all-time low, and she hasn't won a Grand Slam title since Wimbledon in 2010, her longest drought without winning a major since 2005-2007, when she went two years between Australian Open crowns.

She can be perplexing, as with her comments recently about not loving tennis and not even liking sports, but who are we to judge her? She who has won more than any of her contemporaries, only to have her every move watched, recorded and criticized.

Serena Williams is the best tennis player of a generation in a world where to be famous is to be followed and scrutinized day after day after day.

Ali boxed in an era with limited television and zero internet. He was married four times and fathered nine children, not to mention changing his name and his religion early in his career and refusing to enlist in the US Army.

By comparison, Williams' decisions to go clubbing with Kim Kardashian and Tweet a photo of herself on a tricycle seem mighty tame.

Whatever the rest of her career brings, Williams' legacy as one of the greatest female tennis players of the Open Era is set in stone - 13 Grand Slam singles crowns, 12 in women's doubles, two in mixed doubles, two gold medals, 39 WTA titles and 123 weeks ranked No. 1 in the world.

So whatever Williams does or does not do in the next two weeks in Australia, the next year and throughout the rest of her career, let's try and take it with a grain of salt that not a one of us will ever know what it's like to be her.

Learn from Ali: Let's not take 30 years to truly appreciate her greatness.