@Cymelion:
This is the same Crocodile who tried to Kill Luffy several times even after learning his full name which is the same as Monkey D Dragon?
It didn't occur to you that I might have been joking?
But, to keep it going, Crocodile left Luffy alive 2 times, then performed badly in their last fight. Maybe he was so happy his son has become so strong that he let him win while fighting half assed.
And he helped him in the jail and saved his life in Marineford. It was tough love at first, but Crocodile became softer with time. By this progression, they'll be hugging and crying after a couple more encounters.
–- Update From New Post Merge ---
@MarquesaIV:
You guys seriously love to give Crocodile hell because of Ivankov.
Not just because of him. It was mentioned already in this thread, but it seems Shichibukai were inspired partly by the bad guys from the game Romancing Saga 2 (along with real life pirates).
http://en.wikipedia.org/wiki/Romancing_SaGa_2
Check the Antagonists section and tell me it's just a conicidence. If you knew already then disregard it.