He's also one of the most fascinating.
Unlike what some fans wondered earlier in his career, the man is extremely intelligent. He also has a broader perspective on life than merely the single-minded pursuit of excellence on the football field.
As it is, he will go down as one of the best running backs the game has seen. Really.
The numbers aren't going to be as spectacular as they could have been because football never mattered all that much to Williams. He was good at it, so he did it.
But there came a time in Williams' life — think 2004 — when he started to question whether that was all there was.
Had he come back with a different answer, who knows what kind of career he could have put together.
Be clear on this, in terms of pure football ability, Ricky Williams was a top five running back — of all time.
What made Williams special as a running back was his vision, his ability to see where the hole was forming, and then having the quickness to hit that hole.
He is easily the most talented running back the Dolphins have ever had, and it's probably not even close.
It's a shame Dave Wannstedt burned him out by overworking him in 2002 and 2003 because that's what got Williams to thinking about his career.
Williams didn't have a Hall of Fame career, although 10,000 yards is still a major accomplishment, but he likely would have had it if not for the drug suspensions and the hiatus.
How will he be remembered in Dolphins annals? That's a great question, one the organization will have to determine as it pertains to the Dolphin Honor Roll.
His accomplishments on the field merit a spot, but bailing out on the team right before training camp in 2004 has to be factored in as well. That episode, plus the year-long suspension in 2006, probably should keep him off the Dolphin Honor Roll.
Not that Williams is going to care one iota about that. That's football recognition.
Williams wants to be recognized for more than that. For that, we say, good for him.
Covering Ricky Williams was a unique experience for most reporters, other than those who were able to get close to him.
Even though it comes with the territory, he had no tolerance for mundane football questions and made it perfectly clear he did not like talking to the media, especially in group settings.
But get him one-on-one and ask questions with more substance than, "How important is it to establish the running game this week?" and Williams gladly would engage.
This is a guy with a lot to say, even though folks more often were just interested in what he had to say about football.
Williams didn't want to be all about football. He managed in the last several years to find some balance and still produced on the field, putting together a 1,000-yard season for the Dolphins in 2009 and producing as a backup for the Baltimore Ravens last season.
That's why the Ravens were shocked and disappointed that Williams said he was retiring. In the aftermath of the AFC Championship Game loss to New England, Williams had expressed excitement about the way the season went and how much he was looking forward to 2012.
But that quickly changed, with Ricky being Ricky and pulling an about-face.
Like the man himself said, though, it's not like he's not capable of pulling another 180. Maybe he'll realize in the next weeks or months that he really does enjoy football, even if it doesn't totally define him, and his body pretty soon won't allow to play the game anymore even if he wants to.
Or maybe he'll just walk away with no regrets to move to the next chapter in his life.
Trying to predict what Ricky Williams will do is pointless. But if indeed his career is over, all we could do is admire what he was as a football player and appreciate that he accomplished about as much as could without totally giving himself to the game.