When you want to lash out, what are you protecting?  When you want to speak sharply, what truly hurts inside?  Examine what is beneath any lower vibrations such as defensiveness, judgment, impatience, sarcasm, and anger.  Is this issue truly with that other person, or are you hurting, frustrated, not feeling love or loved?  In any case, if you are feeling these vibrations, you are once again identifying with your human story, the role you are playing, instead of with your more basic role as a soul.  Carry on.  Play the role, but take a look at the character you have chosen.  If it is not working, change your script, allowing the heart to guide you.