Our humble service attitude in our life is what determines what effect chanting will have on our consciousness. Otherwise we can be chanting for millions and millions of births before we actually achieve the goal.
Renunciation means death of ego.
Krishna creates excitement in a devotee's life – just like in sport, one-sided game is not very much appreciated, but if it is competitive, then it creates excitement. Similarly Krishna does this during the protection of his devotees.
First we think we are das das anu das, then das anu das, then we are das, then we are prabhu, and then we want to compete with Mahaprabhu.