Detritus and Cheery. If you've read Men at Arms, you already know that one of Detritus's first friends was a dwarf that overcame centuries of cultural prejudice to accept him as a friend and comrade-in-arms. Now, Detritus is returning the favor to befriend and defend Cheery.
One of Vetinari's rare moments of visible emotion, after Vimes told that the religious leaders want to destroy Dorfl.
'I've given that viewpoint a lot of thought, sir, and reached the following conclusion: arseholes to the lot of 'em, sir.'
Angua's story about Mrs. Gammage at Biers. Mrs. Gammage is an old lady who has been drinking at the undead bar since before it was the undead bar, and never noticed the change. She was robbed once. The stolen goods were returned the next day and the thieves discovered to be mysteriously empty of blood.
Dorfl recollecting Carrot's honest kindness and fighting even harder against the king when he notices Carrot later on in the book is definitely a topper.
Why did Dorfl return from 'death'? WORDS IN THE HEART CAN NOT BE TAKEN
No. That Would Be Wrong. We Will Be Freed By Our Own Hands, Or By None.
Cherry spends most of the book with major prejudice against werewolves, not having any idea that Angua is the Watch's werewolf. When she does learn that Angua is the werewolf, after she changed to save Cherry's life, nothing changes between them.
While it's framed via Angua's worry for Carrot, there are a couple of lines which speak volumes of Carrot and Vimes.
"Commander Vimes said someone has to speak for the people with no voices!"
He really believes it, Angua thought. Vimes put words in his head.