Those who believe the axiom that "Ignorance is bliss" only discovered its true meaning when the bliss began to hiss.

Those who believe the axiom that "Ignorance is bliss" are the ones who only discovered its true meaning when the bliss turned to piss.

Those who believe the axiom that "Ignorance is bliss" are the ones who only discovered its true meaning after the bliss turned to piss.

Those who believe the axiom that "Ignorance is bliss" are the ones who only discovered its true meaning when the bliss began to hiss.