Treat everything as a joke. What does this sentence mean?

Hello, this sentence is very profound and contains multiple meanings. Different circumstances, plots and tones express different meanings. Not under special circumstances, you are dissatisfied with real life, dissatisfied with reality, and even don't care about everything in the world. It's all jokes. This is a relatively negative attitude towards life.

If one of the lovers is not joking with the other, then the subtext is "I want to break up with you". Thank you.