Men at Arms/Heartwarming

The shocking reveal as to how Samuel Vimes spent his money before becoming rich. He donated about half his monthly earnings to the widows and orphans left behind by dead watchmen. At the end, he'll probably give it up since Carrot gets Vetinari to approve of pensions for widows.
Cuddy teaching Detritus to count. Aww.
- Later, he saves Detritus from freezing to death. And goes to Quarry Lane to - hopefully - find a troll doctor. And then he threatens other dwarfs for throwing an axe at Detritus.
Detritus's reaction to Cuddy's death. Made all the stronger by Carrot talking him down from obliterating a whole room's worth of assassins shortly afterwards.
"They call me Mister Vimes."
When Gaspode refuses to leave a distraught Angua even when she's growling what's implied to be Canine for "Go away or I'll rip out your jugular".
- Connected with that, too, is the way Gaspode scolded Carrot for drawing his sword when he saw Angua's wolf form ... and then scolded her for not warning Carrot—or giving him a second chance. Particularly bear in mind that Gaspode finds Angua very attractive, and he knows he doesn't have a chance with her if she stays with Carrot.