It's nearly fresh

A passage from Hogfather:

"Would it hurt anyone just occasionally to try to be cheerful?" said the Cheerful Fairy.

"Er... in what way?" said the Senior Wrangler, feeling wretched.

"Well, there's so many nice things to be cheerful about," said the Cheerful Fairy, blowing her nose again.

"Er... raindrops and sunsets and that sort of thing?" said the Senior Wrangler, managing some sarcasm, but [the other wizards] could tell his heart wasn't in it. "Er, would you like to borrow my handkerchief? It's nearly fresh."

I love the Senior Wrangler's final line here. Halfway there to... politeness? Kindness? Feels like his heart's not really in that either. Feet in two worlds.

It's also just a funny line.