“It is foolish for a man to make his misfortunes known to everyone; it is wise to keep them hidden.”
ἐκμαρτυρεῖν γὰρ ἄνδρα τὰς αὑτοῦ τύχας
εἰς πάντας ἀμαθές, τὸ δ’ ἐπικρύπτεσθαι σοφόν.
Ah, fragments. Always so quotable because the culling has been done by someone else already! This one is from the lost Oedipus by Euripides, quoted by Stobaeus (4.45.6).