Boston Celtics guard Marcus Smart is one of the most well-regarded defenders in the league due to his grit, constant hustle and commitment to making plays. That dog mentality isn't born from nothing, and if it's any indication, his AAU postgame ice baths in Walmart trash cans and parking lot fights would explain a lot about his humble beginnings.

The Celtics All-Defensive stud once licked his chops at Flower Mound High School in Texas, but his AAU antics are still legendary.

Per Jay King of The Athletic:

Kenny Boren, one of Smart’s high school coaches and a regular on the AAU circuit: “In Vegas, in between games we’d go to Walmart and … I’m not going to say steal, because we put them back. We’d steal Walmart’s outside trash cans, completely disgusting. Dump them out and fill them for ice baths. Marcus would be sitting in there, f***ing McDonald’s barbecue packets floating in there, and Big Phil (Forte’s dad) is like, “Shut up, just get in there. What matters is you get your ice and shut the f*** up.” French fries floating in there.”

In Texas, playing ball is a profession, no matter whether a player is paid or not. Those grueling two-a-day games with a morning practice tossed in would leave guys like Smart in need for the ice.

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Big Phil also factored in the pressure and hostility that came with being Texas Assault, a ragtag team featuring the now-Celtics heartbeat that won several tournaments with grit and all-out effort:

Forte: “The Island of Misfit Toys. We were a great group, the parents, we all got along and stuff but you know how it is. Egos, personalities, especially when you lose. We had fights in the parking lots, fights with other teams, fights with other parents. Police coming in, escorting our parents out of the gym. It was insane. Kids getting in fights with other kids, parents yelling down at us from the bleachers.”

The Celtics guard's start might not have been touted in the national spectrum, but one can see how those humble beginnings shaped him into the player he is today.

As a young 18-year-old, Smart once set a new Team USA U18 record for steals, racking up a whopping 18 during the 2012 FIBA Americas Championship in Brazil. Andre Iguodala had held the previous record for a decade.