#3. ECW Days (2006-2008)
CM Punk was the biggest crossover star from Indies to WWE in 2006. His hour-long bouts in ROH had already made him a legend and his fans were thrilled to see him what he could do in the world's biggest wrestling promotion. He brought many eyes to WWE's relaunched ECW, which was just seen as a development brand by many. However, he couldn't live up to the hype due to management's lack of interest in making ECW compete with Raw and SmackDown.
Punk was the true MVP of the division, along with Kofi Kingston, John Morrison, and The Miz, but his feuds and matches there couldn't meet the high expectations set by Punk himself. He had some good rivalries with Morrison and Miz for the ECW championship, but his run in the brand did more harm than good to his momentum. But, there was a silver lining as he was not an unknown commodity when he finally moved to Raw in 2008, and it played a huge role in getting him his first big title in WWE.