Anyone who saw Brian Cox as Titus Andronicus at the Swan in Stratford in 1987, can never forget it. I remember seeing a girl in the audience with her mouth hanging open, paralysed, as Titus stunned us with his almost gloating description of his suffering. And what a master Shakespeare was, understanding that when emotion is heightened, it is also complex.
TITUS Ha, ha, ha!
MARCUS Why dost thou laugh? It fits not with this hour.
TITUS Why, I have not another tear to shed.
Humour can also unblock the mind to work creatively in a disaster. But there is also the "We're doomed, I tell ye!" John Laurie type who only cheers up when it's as bad as he always said it would be. Watch out for them, because unconsciously, they may steer events to match their temper.
iTulip explains succinctly, below, the problem caused by the house price crash. For me, though, it's a reminder of how wonderful the old cartoons are.