I recently encountered: 除非，你堅持躲在潮濕的甲殼裡更快樂。in an email.
The context is that the writer was telling me to cheer up.
I can recognize some of these words.
It seems to start off with "unless you persist", but beyond that I'm not very sure what to make of it.
"Unless you persist in making yourself sad, you will become more cheerful" is one guess, but I can't make that out of the remaining words.
"Unless you persist in trying to be happy, you can't hope to be happy" would be another reasonable guess, but again I don't see how to get that from the remaining words.
It's quite possible that both of the above guesses are completely misguided.