I admit that I had to find the mythological reference to understand Erasmus’ simile for looking anxious. 

Yet only just now you were sitting there glum and worried, just as if you’d freshly emerged from Trophonius’ cave. 

 

Note: The cave of Trophonius housed one of the oracles of ancient Greece. Those wishing to consult it had to undergo an elaborate procedure, including painful and frightening experiences, before being told the future.  It was said that anyone who had descended into Trophonius’s cave never laughed again. 

Seems a high price to pay for predictions, which as we know are of a mercurial nature anyhow.  Perhaps better to keep one’s laughter and hope it can help you survive the uncertain waters of the future.    

Source: Desiderius Erasmus (1469-1536), Praise of Folly, trans. Roger Clarke (Richmond: Oneworld Classics, 2008 (1511)), p. 7 and note by Roger Clarke, p. 184

Image credit: Edward Daniel Clarke, Travels in various countries of Europe Asia and Africa. Part the First Russia Tartary and Turkey (1810). Part the Second Greece Egypt and the Holy Land (1813). 2nd edition (1824) (London: R. Watts for Cadell and Davies)