De toutes les choses se¤  rieuses, le mariage e¤  tant la plus bouffonne. Of all serious things, marriage is the most farcical.

-Beaumarchais, Pierre Augustin Caron de
  Le Mariage de Figaro, act1, sc.9.

   Thereare only twostyles of portrait painting, theserious and the smirk.

-Dickens, CharlesJohn Huffam
^9  Miss LaCreevy. Nicholas Nickleby, ch.10.

One can always tell when one isgetting old and serious by the way that holidays seem to interfere with one's work.

-Edwards, Bob (Robert Chambers)
  In Eye Opener, 20 Dec.

Dead men are serious.

-50 Cent originally  CurtisJackson
  The Wars, pt.1, section 20.

Comedy is a very serious thing.

-Garrick, David
Attributed, in conversation with the actor  Jack Bannister.

Speculators may do no harm as bubbles on a steady stream of enterprise.But the position is serious when enterprise becomes the bubble on a whirlpool of speculation.When the capital development of a country becomes a by-product of the activities of a casino, the job is likely to be ill-done.

-Keynes (of Tilton),John Maynard, 1st Baron
  The General Theory of Employment, Interest, and Money.

You cannot be serious!

-McEnroe,John Patrick
  In protest at an umpire's decision at  Wimbledon.

And wine can of their wits the wise beguile, Make the sage frolic, and the serious smile.

-Pope, Alexander
  Odyssey, bk.14, l.520^1.

On n'est pas se¤  rieux, quand on a dix-sept ans. When you are seventeen, you are not serious.

-Rimbaud, (Jean Nicolas) Arthur
Poe¤  sies,'Roman', no.1.

Some people think football is a matter of life and death. I don't like that attitude. I can assure them it is much more serious than that.

-Shankly, Bill (William)
Quoted in the SundayTimes, 4 Oct1981.

I readilyadmit that I am often more serious than I should be at my age or in my present circumstances, yet I know from experiencethat Iamnever lessgiventomelancholy thanwhen I am keenlyapplying the feeble powers of my fallen to be the laughing stock of children.

-Sidney, Sir Philip
  The Defence of Poetry.

Our inventions are wont to be pretty toys, which distract ourattention from serious things. Theyare but improved means to an unimproved end.

-Thoreau, Henry David
  Walden, or Life in theWoods,'Economy'.

If I laugh on that particular day I become so filled with Laughing Gas that I simply can't keep on the ground. Even if I smile it happens.The first funny thought, and I'm up like a balloon. And until I can thinkof something serious I can't get down again.

-Travers, P(amela) L(yndon)
  MrWigg, Mary Poppins's uncle.The'particular day' is when his birthday falls on a Friday. Mary Poppins, ch.3.

Of course we can Learn even from Novels,Nace Novels that is, but it isn't the same thing as serious reading.

-Wells, H(erbert) G(eorge)
  Kipps, bk.2, ch.2.

In England we have come to rely upon a comfortable time-lag of fifty years or a century intervening between the perception that something ought to be done and a serious attempt to do it.

-Wells, H(erbert) G(eorge)
TheWork,Wealth and Happiness of Mankind, ch.2.