why is it so easy to hide the truth

Today, I was reminded why I tend to hide the truth. When I fear I will be disappointing someone, I catch myself "lying", I am not proud of it. I am not seeking a way to avoid responsibility though I am willing to bet that many of us do it subconsciously as we fear the possible consequences to our actions: being blamed, shamed and hurt. In other words, I admit I might catch myself lying to avoid being hurt. I fear I will disappoint someone with the truth. I also notice that I sometime do it to hide my ugly truth: who I am. I have no idea who I am and I certainly fear being someone others won't like. This is one of the reason: I am codependent in my relationships.