User blog comment:WillofOP/Fate of the Fallen/@comment-24769684-20150701014345/@comment-10543621-20150701095106

Also, while both are evil, I think their mental states are quite different. Croco was really not quite as deranged as Doffy is. In that sense, his defeat by Luffy and subsequent imprisonment actually allowed him to think things through and rekindled his desire to traverse the Grandline. The reason he did all that stuff in Alabasta was actually because he lost hope in the challenge for One Piece.

Doffy on the other hand hasn't lost any of his ambitions and his ambitions are nothing short of ruling the world so to speak. He wants to destroy everything the World Nobles own, become the pirate King and essentially the King of the world. Croco's 'looking down on Luffy' mentality was based on his one 'hopelessness' so to speak, kinda similar to Moriah. He feels that there's no chance a rookie like Luffy who has no idea of the terrors of the world can be strong enough to stand against him. Doffy's 'looking down on Luffy' mentality (despite how he claimed to have tried avoiding that) was not based on despair or underestimation of Luffy's abilities, but more so of his absolute confidence in his own.

For someone like that, the effects of being defeated by Luffy should have a rather different outcome than Croco had.