My once-upon-a-time stern and grumpy Grampa being pulled up on stage at the Diamond Horseshoe during lunch to be Ole MacDonald (had a farm E-I-E-I-O!)
Tigger scoffing at DBFF's visor because it was from Sea World.
Getting my sleepy little cousin off the bus back to the AoA resort and she asks me, "Why are we back at Disney World?"
The 100 Acre Wood crew hugging a little Roo plushie to send back home to a sick kiddo.
Watching the MSEP from two unique angles -- once right across from where the floats enter Main Street outside the Emporium and later walking through Cinderella's Castle and catching the very start of the parade coming around the Hub purely by chance.
Peter Pan signing one of his hats for a friend's kid, "fighting" Captain Hook, then flying off to Neverland all within a half hour. Pure magic.
Entering the Haunted Mansion with the sunset and exiting into the pitch black night!
Watching Wishes from behind the castle, then heading back out front along with the villains portion of the music with the good ending music playing right as we get out front. The music timed perfectly making us feel like we had escaped an attack on Fantasyland.
....clearly I can't pick a single favorite.
