Angus MacSpon wrote:

    "I'm not completely heartless and you're starting to act like
Kuno."

    Ranma turned around to face Nabiki.  "What are you talking about?
I'm nothing like Kuno," Ranma said, anger beginning to creep into his
voice.

    "Then why this obsession with beating Ryoga?  Kuno's the same way
about you."

    "That's different, Kuno has no chance of winning against me."

    "And you can't win against Ryoga."  Seeing Ranma's glare, Nabiki
qualified her statement.  "At least not yet."

    "Come on Nabiki, you know me.  I never give up and I always find a
way to win."  Some of Ranma's old confidence seemed to seep back into
him as he spoke.

You raise a very interesting point converning Kuno.

In a sense, Ranma has actually never defeated Kuno.  He's beaten him many
times, but Kuno has never given up.  He's not defeated until he surrenders
the war, and Kuno's never done that.

Of course Kuno has never really learned all that much from his defeats.
Despite what Nabiki says, Ranma isn't acting like Kuno.  He's acting 
like Ryoga.