A primary act of compassion is to lift the load and not add to the load of others.
Easy to say, not easy to do. Can you smile if unjoyful? Can you sing a happy song when you feel like a dirge?
Being true to your little self, no matter how dark it is, might seem like a good idea—if there is a little self, separate from the rest. We may be encouraged to let it all out, whether as a shout or a sulk. The complication is that if you think you are the center of the universe, privileged to make its own weather, you are right. You are the center of the universe, but so is everyone else. If they are to live subject to your clouds and storms, so you do to theirs.
Compassion, of which joy is an instrument, is at the top of the list for two reasons. It is the most powerful. And it is the hardest. So when next you wrap yourself in a blanket of seemingly private sadness, consider that you are most probably not alone. And that the smallest bit of light might be a big gift.