Dirk Nowitzki gazed at the floor as he limped through the tunnel and toward the American Airlines Center home locker room, his sore knee throbbing and thoughts swirling in his head that he might have just played his final playoff game after his Dallas Mavericks were on the wrong end of a gentleman's sweep against the Oklahoma City Thunder in the 2016 first round.

"Dirk! Dirk!" a small voice called, a little boy hoping to get the attention of his hero.

Instinctively, Nowitzki broke his solemn stride, shuffling a couple of steps to his left, extending his hand and making eye contact as they exchanged high-fives. No matter how much pain and anguish he felt, the big German just couldn't leave the little kid hanging.

That impromptu moment, as much as any of his historic accomplishments on the court during a career that revolutionized the NBA, epitomizes the unique bond between Nowitzki and his adopted hometown.

"I left Germany 20 years ago," Nowitzki said after announcing his retirement Tuesday night, "and I became a Texan."

Nowitzki arrived as a goofy kid with a hoop earring, a bad bowl cut, limited English skills and a complete lack of confidence. He grew into a suave franchise spokesman and notorious trash-talker with a clutch resume that ranks among the all-time greats.

So it'd be wrong to say that Nowitzki never changed. He grew up in Dallas, coming a long way from the rookie who wondered if he'd be better off going back to Wurzburg and let unpaid bills stack up before essentially being adopted by a kind woman in the Mavs business office who taught Nowitzki how to handle mundane adult tasks.

But Nowitzki always stayed pure, which is remarkable considering all the accolades he racked up, possessing a humility that made folks in north Texas feel that he was truly one of them. His self-deprecating sense of humor, featured in wacky videos shown during home games for years and on his Twitter account after the geezer finally gave into the social media craze, allowed Mavs fans to bond with Nowitzki like a buddy who would stop by for a few beers.

Nowitzki remained a Texan, and a Maverick, by choice through thick and thin because he took such pride in loyalty, a word printed in all caps across the right toes of the customized Nikes he wore during warm-ups before his final home game, with LEGACY across the left toes.

In an era in which superstars joining forces became a trend, it was fitting that Nowitzki's title came at the expense of a superteam formed in free agency, months after the first of several hometown-discount deals he accepted in an effort to win in Dallas. The Mavs beat the Miami Heat in 2011, getting sweet revenge five years after a controversial collapse against that franchise in the NBA Finals, which was easy fodder for the critics who wanted to write off Nowitzki with the silly, soft-Euro stereotype that he had to shatter.

Dirk Nowitzki brought Dallas a title in 2011, but his impact goes far beyond the court. REUTERS/Hans Deryk

That's why Nowitzki's horrendously off-tune rendition of "We are the Champions," belted out from an arena balcony at the end of a championship parade that had been prematurely planned five years earlier, sounded so good to the thousands of fans who packed the plaza below and sung along in the sweltering June heat.

"I belong to this city," Nowitzki frequently said over the years, often as an explanation for why he took less money to stay or why he never seriously considered leaving even after the front office's ambitious risks backfired following the championship run, ruining his chances of playing on a contender in the twilight of his career.

Nowitzki never failed to back up those words, in triumph and in turmoil, in public and in private.

Millions across the world will remember Nowitzki for spectacular feats on the basketball floor. His name -- and Dirk is definitely all that's necessary for any basketball fan -- will instantly conjure up images on the one-legged fadeaway that stars across the league have copied. Or the way he changed the geography of the game as a trend-setting, perimeter-skilled 7-footer. Or the 2011 playoff run that he capped with a Finals MVP. Or the vintage performance when he lit it up to become the sixth man in NBA history to hit the 30,000-point milestone. And so on.

"I left Germany 20 years ago, and I became a Texan."

But for many, particularly in north Texas, the primary Dirk memories will be personal moments that he made a point to create, simply because he believed it was the right thing to do.

For instance, since Nowitzki became the face of an annual celebrity baseball game, a role he inherited after Dallas Stars legend Mike Modano retired from professional hockey, he has made sure that those who bought tickets got an autograph if they wanted one and were willing to wait in line. (He was also happy to make a fool of himself for a good cause with a baseball swing as ugly as his jumper is pretty.)

He took such great pride in selling out the ballpark of the Double-A Frisco RoughRiders, with all the proceeds benefiting children, that he considered it his obligation to sign autographs well after the stadium lights were turned off, sharing a smile and a quick chat with each fan.

Nowitzki went above and beyond at all of his charity appearances. Take, for example, a team-mandated appearance a few years ago, where each player split off with a small group of vision-impaired children to work on arts and crafts. Nowitzki wanted to have a moment with each child, bending down on a knee, holding the child's hand and quietly engaging in an encouraging conversation. Few noticed this was happening until the end of the event, when the Mavs gathered for a team photo and teammates started calling for Nowitzki, who made them wait for several minutes while he finished.

Then there are the annual visits to Children's Medical Center in Dallas, which were team events early in his career. When those team visits were discontinued for some reason, Nowitzki asked why, and made it clear that he wanted to continue going on his own -- with no publicity.

"Uncle Dirk," as the kids call him, is now a beloved figure in those hallways, including by tragically ill children far too young to understand his fame. Each year, he has team staffers get personalized gift ideas for 15-20 patients and dispatches them with his credit card to make the purchases. He shows up wearing a blue Santa hat and a huge smile to deliver the presents, spending extensive time with the children and their families, often helping to unwrap the gifts and playing with them.

It wasn't until a few years ago that Nowitzki, with the blessing of the hospital and families, finally relented and allowed a Dallas Morning News reporter to trail him during a visit.

It shouldn't be a surprise that a video featuring those visits prompted Nowitzki's most emotional moment during his final home game. He wiped away tears after the video played during a timeout in the second quarter, a moment that will be as much a part of his legacy as the 30 points he scored in the win.

"I believe this is a situation where you have a man who has all of these human qualities," Mavs coach Rick Carlisle said. "He is humble, he is kind, he is great. He is a great competitor, and he has been a guy who is too easy to take for granted.

"It will never be the same without him. It just won't."