Almost anything out of Pinkie's mouth in Chapter X, but especially the self-referential jokes - "We can still have a pleasant introduction! It's not like you're a perfect stranger trying to motivate me into taking a huge step into a philosophical change of character by simply sharing a single melody!" - and the Shout Outs to at least a dozen other fanfics - “The golden harp certainly doesn't mean you study Anthropology, now does it?”
- And not only fanfics - Pinkie noting that Brony Stark is her hero (while Lyra is trying to pull off various introductions from the previous chapters of her journal, no less) is hilarious.
- Also, the moment where Lyra's speech to Pinkie seems to be building up to a breakdown - then she sneezes in Lyra's face. Her reaction is priceless. Extra points for how, in retrospect, Pinkie's body language and expressions over the preceding few paragraphs are pretty clearly setting up a sneeze.
Lyra: Pinkie Pie, there's a time and a place for everything. Don't let anypony make you think that smiling is the only way to feel... to release... Listen. You're a marvelous pony. A beautiful pony. You have so much talent to do so many things. Need they be stifled by a life that is spent entirely on the whimsical mediocrity of the moment? You have the strength and charisma to move mountains, Miss Pie. Where you're pleasantly blowing up balloons and tossing streamers around, you could instead be building a house for yourself and moving out on your own. You don't have to hole yourself up in the Cake family's attic. Don't you think you deserve to start... to start living for yourself and not for other ponies?
Pinkie: But... But other ponies need me...
Lyra: What about your needs, Miss Pie? What about what makes you whole, what guarantees you a future? You may even find that very special somepony if you just tried.
Pinkie: I...I wouldn't want... I wouldn't want to repeat... (Grimacing, as if on the edge of something so painful that her face couldn't register an expression to sum it up).
Lyra: Repeat what? What your family did to you? Pinkie. Listen to me. It's not your fault. ” (gently stroking Pinkie's cheek as her eyes turn wet and glossy. Pinkie grits her teeth and starts to sniffle.) It's not your fault, Pinkie. What they did to you... to kick you out... What they did was wrong. But you have it within you to grow up where they couldn't help out. You can start a family of your own, a family to be proud of, for your friends to be proud of. Tell me... What is it that you truly want in life?
Pinkie: I... I... I... (her lungs heaving and the moisture along her eyes increasing)
'Lyra: Yes? (leans forward)
Lyra: (falling backwards) Gaaah! Sweet Luna on a bicycle!
Pinkie: Whew! I want hay fever to end! What about you!
Lyra: Unngh! Bleachk! Ptooie! Hay... fever...?
Pinkie: Annoying as all get out, isn't it? Heeheehee! Oh! And about my family and stuff. They kicked me out because Gummy made a mess on the carpet for the tenth time in a row!
Lyra: ... ... ... ... ... ... ... ... ...Gummy.
Pinkie: Wow, if I knew any better, I'd imagine you could fill that last breath of yours with a lot of ellipses.