Defense mechanisms that people use to hide behind are sometimes needed for the protection of their psyche and when they have something within their psyche to defend. When people become defensive, they are defending, protecting from revealing behaviors born of their own insecurity, shame, feelings of rejection, guilt, fear, hate, loneliness, ignorance and the like.
People who feel the need to be defensive will use such common defense mechanisms as denial, regression, repression, projection, displacement, rationalization, reaction formation, compensation and intellectualization.
When you have clarity, that is, when you free your psyche from expectations, control dramas, insecurities, and fears by realizing that you cannot be harmed when you are real, that is, when you vibrate from Love, when you live in loving-detachment, you have nothing to defend because you are clear. Coming from a place of unconditional love creates no conditions for you to defend.
Humans find unconditional love difficult thus all the defense mechanisms. As difficult as unconditional loving is, may I suggest that you come out from behind your defense mechanisms by first loving yourself unconditionally and then loving others unconditionally. It doesn't have to happen all at once. It's a process that is best practiced every day. Start small, start with yourself and stop hiding behind these defense mechanism that are only boxing in your soul, your psyche, your feelings, not freeing you to be clear, happy and at peace with yourself.
Don't hide. Allow yourself to be vulnerable (admitting how you really feel) by revealing the love inside of you. It's there and cannot be harmed, contrary to popular opinion. It's better, from my experience, to live in a reality where you have nothing to defend. Hey, defense mechanisms hurt.