Feelings are the mirrors of events happening with you, that is why do not try to stop your feeling, always explore your feelings when you get the chance.  Suppose you are sad and you are not showing it then it will make you more tense, but if you express those feeling than you feel relax and better than past,  When you are happy and then if you are sharing with other people they might be your relatives or your friend, you will get more joy and some more reason to get happy.

So do not simulate your emotions.