Often when you are happy you feel life is a dream because you do not believe it is real. When there is misery you feel life is a burden, and sometimes your misery is because you take trivial things too seriously. But if you have really gone through pleasure, you realize that pleasure is a burden, and if you have thoroughly undergone misery, you realize that life is a dream.
When you realize that you have been carried through every miserable situation, then you know life is a dream. And in between the pleasure and the pain, life is all a joke. Life is very uncertain. Before it takes you away, realize it is a dream, a burden or a joke.
What about life is a joke? You do not question a joke. If you question a joke, it is no longer a joke. Do not question a burden either. It is a waste of time to question life and its events.
A burden makes you go deep. It takes you to the core of yourself. Awareness of dreaming wakes you up and seeing life as a joke makes you light. The only certainty is that life is a dream, a burden or a joke, and only when you realize this can you be centered.