When asked about his huge Game 6 in the Western Conference finals two years ago, Klay Thompson credits hard work before making a joke. (0:53)

OAKLAND, Calif. -- It took a few minutes to figure out what was eating Klay Thompson. We had always had a good working relationship, so I knew it wasn't anything personal. The conversation was flowing well. He was funny and introspective and wise in that all-over-the-place way his teammates adoringly call "The Klay Thompson Experience." But during the entire interview, he just seemed a little distracted.

Finally, I noticed the paper in his right hand. He kept looking at it, the way you check your cellphone over and over when you're being careful not to miss a text.

"I have to get a new driver's license," Thompson says after I ask what the paper is for.

Is it expired? Can't you order a new one through the mail?

"No, I lost mine. So annoying," he says. "But we got a hookup at the DMV. So I just go in and out."

Perfectly reasonable. Except that, yooooo, this is four-time All-Star Klay Thompson running his own errands at the DMV -- in Oakland, a few miles from where the defending NBA champion Golden State Warriors play their home games. Can you imagine the crowd he attracts strolling in?

"That's not the first time he's had to get a new license, either," associate head coach Mike Brown says with a hearty laugh. "When I moved to California last year, I had to get a new license. I went in there and the lady was like, 'One of your players is always in here.'"

Brown smiles. He loves Thompson. The whole coaching staff does.

"I wish I was Klay Thompson," head coach Steve Kerr says. "I envy him. He doesn't really care what anybody thinks. But the way it manifests itself is so natural and normal. He just loves to play, he loves his days off, he loves getting outside, loves the beach.

"He's not low-maintenance. He's no-maintenance."

It's not just charming, it's a key reason the Warriors have been able to become a superteam on the verge of their third championship in four years. They hold a 3-0 series lead over the Cleveland Cavaliers heading into Game 4 of the NBA Finals on Friday night.

"He could very easily have been the type of player who wanted to go elsewhere so he could have his own team, and there's nothing wrong with that," Kerr says. "But because he's not, he has no problem just playing his role. And he's so good at it. He's just a machine with his shooting and just his approach. He never, ever gets tired. He guards the opponent's best guard night in and night out, and then he runs around like Reggie Miller and makes shots."

"He's not low-maintenance. He's no-maintenance." Warriors coach Steve Kerr

On the court, Thompson's defensive ability makes up for the slender, 6-foot-3 Stephen Curry's physical shortcomings. Thompson is a deadly catch-and-shoot scorer who doesn't need to dominate the ball to make plays or get himself going -- essential on a team with former league MVPs Curry and Kevin Durant, who do need the ball a lot.

And then there's the personality.

"If he had a huge ego, this doesn't work," Warriors forward Draymond Green says flatly. "It just doesn't."

Those who know Thompson best say there is an ego in there. It just manifests itself differently than almost any other All-Star. He's ultracompetitive, yes, but without the chip on his shoulder.

"I have never heard Klay say, 'This is B.S. ... This guy is shooting too much, that guy won't pass, or I'm not getting enough looks,'" his agent, Greg Lawrence, says.

"If he has a bad night, Klay will say, 'I wasn't good tonight. I couldn't make anything.' Most guys would be like, 'The system sucks' or blame it on a teammate or coach."

Klay Thompson's lack of an ego is what allows Golden State to deploy one of the game's best two-way players as its third option. Cary Edmondson/USA TODAY Sports

JOEDY GARDNER COACHED Thompson in high school and at the AAU level. Back then, Thompson was just former Los Angeles Lakers center Mychal Thompson's kid and Trayce Thompson's older brother. Washington State and Notre Dame were the only colleges that recruited him with any gusto before his breakout senior season.

"I think the drive came between his sophomore and junior year, when nobody respected him," Gardner says. "He wasn't even a player to watch. Mychal would tell everyone, 'My kid's going to be good,' but I don't think anyone believed him."

Thompson channeled that drive into relentless on-court work. He'd train in group sessions with Gardner every Monday and Thursday night at the San Juan Capistrano Boys & Girls Club. Then they'd do personal sessions, scheduled and unscheduled.

Day after day, sometimes deep into the night, Gardner would hone Thompson's shooting form into the fundamentally perfect quick release you see today. There was a drill in which Gardner would drop a hula hoop over Thompson's head at a 45-degree angle as he shot so he would stay straight up and down. Another drill in which Thompson would shoot with a hat on to keep his head steady and trust where the ball was, without looking at it. And, of course, the drill in which Gardner would hold a towel and rubber bands below Thompson's arms, to keep his top half high without bringing the ball down -- ever.

"I had Klay from such a young age, it really helped," Gardner says. "And he still comes by to work. He'll just show up out of the blue at my house, like, 'I wanted to get some shots up.'"

Warriors assistant coach Chris DeMarco has worked with Thompson personally since his rookie season. By now, DeMarco is used to the texts asking him to come back to the facility at night so Thompson can get up extra shots.

"More than anything, he just loves the game. He loves playing basketball, and he loves shooting," DeMarco says. "He's like a kid in the backyard, just playing for hours."

"If he had a huge ego, this doesn't work. It just doesn't."

There's a simplicity of focus in all the characterizations of Thompson that's hard to reconcile with the flaky, laid-back guy who keeps losing his driver's license.

How can a person be so laser-focused on one thing and so unfocused on everything else?

Simple. Basketball matters deeply to him. The other stuff doesn't.

"I usually wake up, go to the facility, get breakfast, get my shots up. About 100," Thompson says casually. "I'll get stretched, ice tub, maybe get Subway. Play with [my dog] Rocco in the backyard. Take a nap. Go to the arena. Have fun. Hopefully we win. It's that simple. I do that 100 times a year."

He doesn't freak out if there's any disturbance to that loose routine. Like, for instance, when he overslept and missed practice the day before the game he scored 60 points in three quarters against the Indiana Pacers last season.

"I was already an hour late once I woke up, so it wasn't worth going at that point," he says. "I could just go back later."