1
general::
Phrase(s): Where ignorance is bliss, ’tis folly to be wise.
Prov. If knowing something makes you unhappy, it would be better not to know it. (Also the cliché: ignorance is bliss.) • Ellen: The doctor didn’t tell Dad that Mom probably won’t recover from her illness. Do you think we should tell him? Bill: No. It would only make him unhappy and ruin their last months together. Where ignorance is bliss, ’tis folly to be wise.
McGrawhill's American Idioms And Phrasal Verbs