Jim Calhoun, the former coach of Ray Allen during his time in the University of Connecticut, was a first-hand spectator to the rise of Allen from a budding star to a full-blown NBA prospect. It would be safe to assume that Calhoun is an authority on Allen, so when the former coach described the Hall of Famer as “obsessive,” there must be some truth to it.

Calhoun sat down with Mike Anthony of the Boston Herald to discuss his experience in coaching Allen for three celebrated years.

“You can talk about his form, which is beautiful, his elevation to keep the ball up there, his incredibly disciplined work,” Calhoun said. “We’re really talking, eventually, about self-belief. He’s obsessive, in a very good way. Ray is different. He is one of the most meticulous people.”

According to Calhoun, Allen was so fixated on getting things perfectly during practice that he almost ran every single person out of the gym.

“Doc Rivers and I have talked about this,” Calhoun said. “Ray would wear out two ball boys before practice. … Ray practiced perfect. And when you practice perfect, and combine that with (talent) and winning, what do you get? Hall of Fame.”

The 76-year-old, three-time NCAA champion coach also described how coachable Allen was. The 10-time All-Star's passion and determination were always on display, even at a very young age.

“With Ray it was, ‘Just show me the map, give me the markers how to get there,’” Calhoun said. “He was smart enough to understand what was important, what wasn’t important. Ray came to us with a thirst to be great as much as any person in anything.”

Allen is considered by many as one of the greatest shooters of all time. However, as explained by his former college coach, his greatness is more a product of hard work and fortitude as opposed to a God-given gift.