You can't build a plot out of jokes. You need tragic relief. And you need to let people know that when a lot of frightened people are running around with edged weaponry, there are deaths. Stupid deaths, usually. I'm not writing 'The A-Team' - if there's a fight going on, people will get hurt. Not letting this happen would be a betrayal.

Sometimes it is better to light a flamethrower than curse the darkness.

This is Art holding a Mirror up to Life. That’s why everything is exactly the wrong way around.

He found that he had this sudden desperate longing for the fuming, smoky streets of Ankh-Morpork, which was always at its best in the spring, when the gummy sheen on the turbid waters of the Ankh River had a special iridescence and the eaves were full of birdsong, or at least birds coughing rhythmically

Good and bad is tricky," she said. "I ain't too certain about where people stand. P'raps what matters is which way you face." (pp. 348-349)

The fastest way to travel is to be there already.

Progress just means bad things happen faster.