Kevin Durant received a ton of flak when he decided to leave the Oklahoma City Thunder to play alongside Steph Curry and the Golden State Warriors. The criticism has only increased after he joined the Brooklyn Nets and then demanded to be traded when his four-year extension was just about to kick in.NBA greats Charles Barkley and Shaquille O'Neal have been among the most vocal critics of Durant. On an episode of "The Odd Couple" podcast, Fox Sports producer Rob Guerra stated that the criticism stemmed from personal problems Barkley and O'Neal may have with Durant.“It seems like he’s become America’s favorite punching bag. And it’s unfair to me…Charles Barkley, specifically and Shaq, maybe to a lesser extent, it feels it’s personal to them, like they have something personal that they don’t like about Kevin Durant.”Guerra said the fact that Shaq and Barkley are Hall of Famers could be why they are so harsh on KD.“Maybe it’s because both of them are Hall of Famers, Shaq easily a top ten player of all time, Chuck right there on the outskirts, on the periphery, that they compare him to LeBron, to Michael Jordan, to Tim Duncan. And so, Kevin Durant talent-wise can match up with those guys, but he’s shown that the intangible part, that’s just not him, that’s not where he’s at, that’s not his psyche.”“But because he doesn’t line up with those guys, he’s the worst, and that’s not just fair! Charles Barkley didn’t win a championship. Chris Paul is lauded as one of the great leaders of this generation, and he made the finals once and blew a 2-0 lead.”Timothy Bella@TimBellaCharles Barkley's take on Kevin Durant being "Mr. Miserable" and an "abject failure" as a leader comes four months after Chuck feuded with Durant over the "bus rider" comments -- and then drove an actual bus on "Inside the NBA." twitter.com/i/status/15191…gifdsports@gifdsportsThey really let Charles Barkley drive a bus. Inside the NBA is on another level 146They really let Charles Barkley drive a bus. Inside the NBA is on another level 😂 https://t.co/NlYNVl7XdbCharles Barkley's take on Kevin Durant being "Mr. Miserable" and an "abject failure" as a leader comes four months after Chuck feuded with Durant over the "bus rider" comments -- and then drove an actual bus on "Inside the NBA." twitter.com/i/status/15191…Charles Barkley takes another shot at Kevin DurantCapital One's The Match: Champions For ChangeAfter his “bus driver” comments about Kevin Durant went viral, Charles Barkley returned to take another shot at the Nets forward. He called Durant “Mr. Miserable” and an “abject failure” during an interview with Brickley and Marotta on Arizona Sports.The “Mr. Miserable” moniker was used to describe Durant’s head-scratching move to demand a trade out of Brooklyn. When he didn’t get traded, he issued an ultimatum and tried to force team owner Joe Tsai to fire GM Sean Marks and head coach Steve Nash. Despite none of his demands being met, Durant has reportedly committed to the Nets for the long haul.“He seems like a miserable person, man. I call him Mr. Miserable, he’s never going to be happy. Everybody’s given him everything on a silver platter. He was the man in Oklahoma City, they loved him, he owned the entire state. He bolts on them and wins back-to-back championships (with Golden State), and he’s still not happy. Then he goes to Brooklyn, they give him everything he wants and he’s still miserable.” View this post on Instagram Instagram Post"If you go back and look at his career, as the best player and being the leader that all goes with that, he’s been an abject failure. Every time he’s had to be the leader and best player, he has not had success. That’s what us old guys think about him."The “abject failure” dig was a shot at Durant for not delivering a championship to the OKC Thunder as a leader and franchise player. Barkley’s comments about Durant’s failure to win a championship on his own seem out of line considering he didn’t win one either. In Barkley's lone trip to the NBA Finals, he was destroyed by Michael Jordan and the Chicago Bulls.Whistle@WhistleSportsHakeem Olajuwon. Scottie Pippen. Charles Barkley.The Big 3 did NOT go according to plan for the Rockets in the 90s 11131Hakeem Olajuwon. Scottie Pippen. Charles Barkley.The Big 3 did NOT go according to plan for the Rockets in the 90s 🚀 🚫 https://t.co/Qil0sjolRsWith training camp still weeks away, Durant and Barkley's back-and-forth will help keep things interesting in the offseason.