I think he sees no as a challenge; either to his authority or as one he needs to seduce depending on his mood. [A note of fondness creeps into his voice as he speaks. Those same things that bother Spike so much about Jack are the same things he loves. He loves watching him be a hero, someone he aspires to be. He loves that Jack can make the hard decisions, the ones that save the world, that no one else can make. And more importantly he loves being the one who is there for him at the end of it all.]