Why do we hide our emotions from ourselves?

Why do we hide our emotions from ourselves? There is an irony in using our emotions as a defense mechanism. We push our emotions away in order to get to our happy place, but we cant find our true happy place because we are suppressing our emotions.

looking back on my childhood I don’t remember ever really being happy. Its interesting because many people tell me I’m a happy person. Sometimes people even ask me, how I can be so optimistic when I went through such shit? The truth is I was not always like this, and I did not always know what made me happy. Of course when someone gave me a gift, I would say thank you and acknowledge there kindness. Sometimes I really loved the gift or the card, but I still found it hard to be truthfully happy. At the time it seamed that I just did not know how to respond. Now however I understand that I was suppressing my emotions because I did not know how to let myself enjoy life.
In my journey of trying to get the acceptance from my foster family the same times as I was trying to get acceptance from my biological family, I somehow berried my emotions and forgot where I marked the spot. All I wanted was just wanted to fit in. One might say that my emotions where under developed because I had a need to study other peoples emotions. What I am trying to say is sometimes I would study the people around me to try and see how they act and what made them happy. Sometimes I would test them buy giving them something or sharing something with them that was of value to me. I studied them because I did not know why they could not accept me even though they asked me to come join them. In my foster home, my foster family acted different in almost every situation then my biological family. My foster family even spoke differently, sometimes they where sarcastic and I did not know when they where serious. My foster mother would tell me that I was superficial. The truth is, I was superficial but only because I was hurting inside. I could not find a way for them to accept me so I did not constantly feel criticized. Honestly I still don’t understand how they wanted me to be myself, when I was only aloud to act like them?
I faced similar situations in collage because I kept finding myself in relationships where I was still hiding my emotions from myself. Putting up with bosses and coworkers that treated me like shit, only because I needed but in reality the job was bringing me down both physically and emotionally.
I think the first time I was really happy was the day my son Knox was born. The first time I looked at his face, I had an overwhelming feeling of happiness. It was so real and so deep that it almost felt like fear. It was as if somebody had spilled a bucket of water over my sleeping body. I was awoken with all these emotions and feelings that I had been keeping from myself for so many years. At that moment I made a promos to myself that I will try to be honest with myself. I need to be at my best, to be at my best for my son and now my daughter.