Creeper

“Anger was a weapon to be honed and treasured and used only at the moment yielding most premium.”
― Terry Pratchett, Raising Steam

“You can't be loony and rich. You've got to be eccentric if you're rich.”
― Terry Pratchett, Reaper Man

“In fact he was incurably insane and hallucinated more or less continuously, but by a remarkable stroke of lateral thinking his fellow wizards had reasoned that, in that case, the whole business could be sorted out if only they could find a formula that caused him to hallucinate that he was completely sane.*

*This is a very common hallucination, shared by most people.”
― Terry Pratchett, The Truth: Stage Adaptation

“He had died for his beliefs; chief among them was the very Hugglestonian one that bravery could replace armour, and that Klatchians would turn and run if you shouted loud enough.”
― Terry Pratchett, The Truth: Stage Adaptation