Twilight Sparkle: That would be nice, Spike, but what if something else came up while we were gone? What if we were delayed getting back and I wasn't able to finish everything on that list? What if we lost the list on the way to Ponyville and then couldn't remember which things we'd done and which things we hadn't done, and then spent so much time trying to figure out what we hadn't done and what we had done, and we ruined the entire Celebration by not doing the one really important thing that we were supposed to do?!