I find we are growing serious, and then we are in great danger of being dull.

Artistically he became a disciple of John Dryden. (This is usually paraphrased as "Hell hath no fury like a woman scorned")
Congreve coined another famous phrase in Love for Love (1695):
"O fie miss you must not kiss and tell. Later life
Congreve withdrew from the theatre and lived the rest of his life on residuals from his early work.