Yeah, you are right balance is the key to live a happy life :) yes I'm talking about balance in everything.
Our life is also divided into two parts,
one is dark (sad)
one is bright(happy).
If you are sad cuz of something, Don't let this sadness ruined That part of your life :)
Try to overcome this sadness by balancing it by happiness and by thinking beautiful moment of your life :0
if you happy, don't get too much :) the overdose of happiness is also harmful to our health and for our soul.
Too much happiness also makes you selfish, So try to remind the hard days of your life or try to remind those people who don't have this happiness :)
if you can help them? do help them.
Thanks.