This book manages to create a CMOH and a CMOA at the same time with just three words: "I have worth."
The other passengers in the coach defending Nutt from the Furies.
Ponder Stibbons was offered the post of a Bursar in the new University of Brazeneck. How much would they pay? He didn't ask. Awww.
"I wrote it for you."
Archchancellor Ridcully's reaction when the Librarian was poisoned. Most of the time Ridcully seems to be the boisterous, thoughtless type, but his anger at the poisoning shows that, in his way, he truly cares for his friends.
Upon finding out that new arrival Professor Macarona is a Straight Gay, Ridcully has this to say "A lot of that sort of thing about, apparently ... people make such a fuss. Anyway, in my opinion, there's not enough love in the world."
If the striker thinks he scores, or the keeper cries in shame...
Its pretty minor, but Vetinari telling the rest of the football captains to take home the guy who just slapped him on the back and spoke to him in a rather crude (albeit friendly) manner and told them to make sure no harm came to him (by which he explicitly means "put him on a suicide watch", since once he realises what he did, he might try to kill himself). That and him showing a sense of humor other than pure sarcasm for once really humanized him.
When the team is put on a fast for the night, Ridcully discovers that Mrs. Whitlow has gotten to all his secret hiding places for booze and tobacco. Until he finally gets to the most secret of all and finds it still there...along with a note from Mrs. Whitlow: "I didn't have the heart."