Christian Braun was in basketball prison. The family pickup truck was his cell. The rest of the game was his punishment.

He waited awkwardly in a lonely parking lot for his friends and mother to leave the gym. At the time, it was a nightmare that he desperately wanted to forget. Over the years, it became a defining memory worth telling other coaches.

Braun's path to his third Opening Day in the NBA was one of victories. Almost complete. He won three straight state titles at Blue Valley Northwest High School in Overland Park, Kansas. In his final college season, he led the Kansas Jayhawks to their fourth NCAA Championship. As a rookie the next year, he contributed to the Nuggets' first NBA championship.

The overwhelming team success gives additional resonance to Braun's rare moments of failure or disappointment. They are twice as memorable for him. Twice as educational. As he prepares for another potential career milestone and highlight on Thursday – replacing Kentavious Caldwell-Pope as Denver's starting two-guard – his new role requires a healthy balance between two contradictory, co-existing sides of his basketball personality: the small-town -Kansas and Kansas City; cockiness and humility; old and new.

“I think you have to know who you are,” Braun said in an interview with the Denver Post this preseason. “You have to be very aware of your situation. …You have to have a balance. You have to understand that you are still at the bottom. I'm still trying to get to the top. There are things you have to earn, things you have to prove before you do that. But my teammates know. I make little clever comments here and there. So I'm still me. I am still who I am. With every level I reach, I just get a little calmer.”

Braun hadn't quite mastered that balance when he found himself in that truck. Back at the gym, Braun's mother, Lisa, coached his rec league team. She is a former Division I player herself and an All-Big Eight honoree at Missouri. She could be harsh on her son, and he could cross the line of insolence with her. You are very close to this day.

“He was by far my loudest child,” she said. “And my bravest child.”

The details of how Braun ended up there are somewhat unclear. Lisa thinks it's related to a defensive breakdown. Christian kept insisting to her that it wasn't his fault because he was in the right position, while she tried to teach him that it didn't matter who was to blame. Christian thinks it could have been the offensive. He started three-pointers from too far away and didn't share the ball enough.

Whichever version is correct, Lisa was right. Christian didn't want to hear it.

“She told me not to do it. Of course I did it again. I looked at her. She took me with her,” he remembers. “I came to the bench. She obviously told me what I needed to do. And I made a comment to her because I'm just a smart young kid. Something fancy, I’m sure.”

“I said, 'Christian, sit down.' He sat down on the bench. “Still he chews on me,” Lisa remembers. “I said, 'Go to the end of the bench.' And the whole time he was down there he started yapping.”

That was the breaking point. Lisa pulled out her car keys and tossed them to Christian.

It's one thing to sit on the bench. It's quite another to be thrown out of the building.

He was quiet during the drive home. There wasn't much to say. The coaching maneuver hurt him where it hurt most: his desire to be on a basketball court. “I think punishing him by not even allowing him to be there was probably a big blow to him,” Lisa said.

Braun's childhood in Burlington, Kansas (pop. 2,600) was dominated by sports. Unlike some of his friends, he wasn't interested in first-person shooter video games like Call of Duty. All he wanted to do was play NBA 2K or Madden NFL. He spent most of his free time outdoors, swimming or fishing in the lake next to his house. Both of his parents entertained him with stories from their college basketball days. Table conversations were often about LeBron vs. Jordan, with Christian pitting himself against the older generation to stir things up. When it snowed, he rushed to shovel the “bare necessities” out of the driveway, his mother says, just enough to make room so he could play basketball with his brother, Parker.

“He wouldn’t do it to get my car out of the garage,” she said.

Family sports were Braun’s favorite sports. And he was best at that. In a rural community, competition was low. He found that if he tried hard, he could dominate.

Nothing else has ever appealed to him as a career.

“I was really into basketball. To be honest, I never had any interest in it. I wish I had,” Braun said. “But I was never interested in school. I was never a good student. … I was that child. I was in a bit of trouble. Nothing bad, but I was always the one who talked too much in class.”

During an elementary school class in which students were expected to choose from a variety of books and ultimately take reading tests, Braun and his friend Tegan Hess thought they could manipulate the system. They huddled at the computers in the back of the room where the teacher couldn't see them and opened the test to a Harry Potter book they hadn't read yet. When they tried to guess the answers, they almost failed, so access to the tests was eventually protected by a password. “We got 20 and 30 percent,” Hess said with a laugh.

Their basketball and football teams were unstoppable throughout middle school. Braun was one of the main reasons for this. But the memories that remain now are not so much the victories. There was the infamous Wellsville game in which Braun shot 4 for 22 from the field, wiping out an undefeated season. “It’s probably the worst game I’ve ever played,” he claims. “I was embarrassed.”

And then there was the expulsion from the gym, courtesy of mom. This proved to be a turning point, perhaps even a revelation. At that moment, “I kind of thought, 'Oh God, maybe I shouldn't have done that,'” Lisa said. But her son didn't rebel during a game the rest of the season.

The Brauns soon moved to the suburbs of Kansas City, where there was a more vibrant youth basketball scene. He fully embraced his one interest and joined an AAU program called MoKan. His trainer there, Drew Molitoris, was amazed at how coachable and mature Braun was. So did Ed Fritz, the coach at Braun's high school.

“The coaching staff could bring him in and he would have a good overview of the team,” Molitoris said. “He was respected by his teammates and his coaches alike, whereas certain kids are often viewed as teacher's pets where coaches use them to get information about the locker room. “CB could always master that type of leadership role.”

“Everywhere he goes,” Fritz said, “people just love him.”

The simple explanation: Braun has simply grown up.

The more nuanced one: his personality was forced to adapt to his surroundings.

There is some truth in both, Braun believes.

“I was calmer during class. But then if I went home, I would still be the same. “A little cocky, competitive kid,” Braun said. “I was always the best player in my small town. Then when I went to the Kansas City, Overland Park area, I was never there. I was the same person. Deep inside. I still had the same confidence, a little bit of the same cockiness, but I couldn't be (outwardly the same). Because I wasn't the best player. I was 1.70 meters tall.”

Luckily for his dream, his work ethic was eventually rewarded with a growth spurt – he's now 6-foot-2 – and paved the way to the NBA. But his surroundings were never what they were in Burlington again. He enrolled in a blueblood college program at KU, where the roster is consistently star-studded. And he was drafted by an NBA franchise that was already on the precipice of a championship, led by a two-time league MVP. Modesty has been non-negotiable for years.

However, confidence is still the driving force behind Braun's game. The Nuggets need him to attack with reckless abandon in transition, to guard opposing superstars with tenacity and to take the open shot when defenders underestimate his role in the starting lineup. The disobedience that led to Braun's removal from the gym may have been a trait that needed maturing, but the underlying swagger and cockiness are essential to what his current coach, Michael Malone, wants from him.

“Sometimes you can see it on the pitch when I scream or do things like that. So it’s coming out,” Braun told The Post. “The older you get, the more you get used to the people around you, you tend to open up and be more who you are. And these guys let me be myself. Coach Malone let me be myself.”