I wrote an essay about the importance of rage, kindess (as opposed to niceness), and justice as highlighted in Pratchett's work, and posted it in a group of Pratchett fans on Facebook. It went like this:
This one [is directly relevant to Pratchett and his work] and covers: Anger and Kindness, among other things.
It's taken me a while to work it out, but one of the reasons why I still engage so strongly with Pratchett's work is because of these two themes running through the thoughts and actions of pretty much every main character to whose point of view we get to bear direct witness. That, and the notion of Justice as opposed to Mercy.
Pratchett's main characters are almost all angry, often as a ground state of being - Granny Weatherwax and Commander Vimes springing immediately to mind. Polly Petks (and, to be fair, pretty much everyone except perhaps Lieutenant Blouse in Monstrous Regiment), Archchancellor Ridcully, The Patrician, Susan Sto Helit, Esk, Glenda Sugarbean, Agnes/ Perdita Nitt, Angua von Uberwald, and Tiffany Aching, to name a few more, are people to whom rage comes easily, and is a motivating force. Even those who are seen as generally more easygoing or placid of temperament have illuminating moments of anger which tip them over the edge to somewhere inspired, and that click of fully engaged rage is often a pivotal moment (for a near perfect example: Magrat's core is revealed to be sheer, molten ire when her personality is ablated by the Faerie Queen).
That's not to say that inchoate choler is venerated - the malicious, bubbling spite of Corporal Strappi is vilified as destructive, and the ever-seething, undirected bile of Mister Tulip is likewise outlined as useless because he is unable to focus it himself (hence depending on Mr. Pin's guidance).
Which brings us to kindness. Pratchett's heroes have all realised, at some level or other, that anger is a force that can - and should - be used for good. Weatherwax and Vimes, in particular, are constantly vigilant against the darkness inherent inside themselves which could snap at any moment under the weight of a wicked world and set it alight for a better one to be rebuilt from the ashes. They know that they shouldn't (it's pretty much treating people as things, after all), but that's ever constant. That's not to say, however, that the anger is never shown, utilised openly, or acknowledged by those around them. Vimes and Granny have both owed their survival against powerful, wicked creatures to rage's primal surge, but also to the enormous, almost terrifying love they bear the world.
Granny tells us that kind is not the same as nice. Nice is pretty, petty, and a lie. Nice is slapping an attractive plaster over a wound without cleaning it properly first, or dealing with the thing that caused the injury in the first place. Nice paints a gloss over injustice and asks us all to be quiet for the sake of those for whom the world works just as it should. Nice is self-delusion, and a wilful one at that. Which isn't to say that we should never indulge in a little of that - peel every cover off the world and it's too much, too raw, all at once, and we all need our masks in this world of fake it til you make it - but the Turtle cannot move if it never acknowledges the epic tides against which it must strive, and the Turtle Moves. It must.
Because justice moved Pratchett and, through him, all his finest creations. His villains were remarkable for their ability to subvert justice, to delude - themselves and/ or others - and to take and take for the sake of sometimes strange, but, all too often, all-too relatable motives. Money, power, comfort and, above all: control. And his heroes were glorious for their ability to see past the smoke and mirrors, the age-old inequities held up as a normalcy that must be protected at all costs, and tear through unjust conventions to make the necessary changes for everyone to step that bit closer to being truly free, with all its inherent terrors and responsibilities.
Pratchett wasn't nice, or whimsical - he was angry and (increasingly explicitly) vocal about justice in his works. And none of his heroes - our heroes - are either. They are kind, they serve justice, and they kick arse on behalf of those with less power, but they are neither nice, nor insipid, nor silent. And neither should we be.
Change is uncomfortable. Change feels like a death, which is why, no matter how positive the shift, we all move through the grief cycle of denial, anger, bargaining, depression, and finally acceptance and exploration. True bravery is being afraid of the pain of righteous change, of letting go of who we were, of bidding farewell… and doing it anyway.
Be brave, [Pratchett Fans]. Be bold and angry and loud about justice, and strive for true equity.
The Turtle Moves. And so should you.