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While some kids dream of being Spiderman or Batman, 4-year-old Carter Lawson has a different hero in mind: Mailman.

Each day Carter stands by his window in Knoxville, Tennessee, brimming with anticipation to see Mike Crenshaw, known to him simply as "Postman Mike."

So when Carter got the invitation to tag along with Crenshaw and visit the U.S. Postal service’s sorting center in Knoxville, he was overjoyed.

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“I’ve got to get ready for Postman Mike,” he said.

When they’re on the job together, Crenshaw keeps his pint-sized postman in check, ensuring his eagerness to do the job doesn’t slow him down.

“You don’t throw the mail!” he said, as a box went sailing through the air. You’re going to get fired,” he said, jokingly. “What’s fired mean?” he asked in reply.

For Crenshaw, the friendship with a 4-year-old is an unusual one, but it’s something he wouldn’t exchange for anything else.

"We just hit it off,” he said. “You never know who you’re gonna become friends with. It could be a 4-year-old child, it could be a 94-year-old man."

Carter Lawson(left) and Mike Crenshaw(right) have formed a friendship over the mail.

Carter’s mom says just a few minutes of kindness each day makes a difference for him.

"When you’re a child, so much of life is more magical," said Cassie Lawson, Carter’s mom. "I think it’s really sweet because it’s not a celebrity, it’s not a pop star, it’s just your average guy who has a seemingly regular job."

Back at the Post Office, Crenshaw’s coworkers were so touched by their colleague’s story that they invited Carter in to witness the sorting process and learn more about how the mail is delivered.

They, too, were just as taken as Postman Mike with his keen fascination for how the mail system works.

“He sent a letter to one of his grandparents down in Texas,” said Crenshaw. "I said, 'We'll get it there buddy.' He said, ‘Phew, you got a long way to drive.'"