The Personalities of Presocratics (Aelian, Varia Historia 8.13)

“They say that Anaxagoras the Clazomenian was never seen laughing or smiling from the beginning. They also say that Aristoxenos was hostile to laughter with all of his strength and that Heraclitus used to weep at everything in life.”

᾿Αναξαγόραν τὸν Κλαζομένιόν φασι μήτε γελῶντά ποτε ὀφθῆναι μήτε μειδιῶντα τὴν ἀρχήν. λέγουσι δὲ καὶ ᾿Αριστόξενον τῷ γέλωτι ἀνὰ κράτος πολέμιον γενέσθαι ῾Ηράκλειτόν τε, ὅτι πάντα τὰ ἐν τῷ βίῳ ἔκλαεν.

A dinner with this trio might not be too pleasant. Perhaps it would be better if we invited Democritus to the party:

Suda s.v. γλουτῶν

“Democritus of Abdera was called the “Laugher” because he laughed at the useless seriousness of human beings”

ὅτι ὁ Δημόκριτος ὁ ᾿Αβδηρίτης ἐπεκλήθη Γελασῖνος διὰ τὸ γελᾶν πρὸς τὸ κενόσπουδον τῶν ἀνθρώπων.