Some of the memories, when you get a sneak peek of life in the Liddell family and realize that Alice had a stable, loving home and family. Keyword is had, and it's kind of sad when you remember what happens next... Downer Ending much?
The ending of the game. YMMV on this, but seeing the once-decrepit, dark and dirty London brightly lit with a blue sky, with colourful mushrooms growing out of the cobblestones and objects from Wonderland... This troper finds that ending very heartwarming, now that Alice can view the world in a happier light.