The "Don't" video looks like billiards balls on a break, which might be the feel certain apps are going for, particularly games. It doesn't make sense for a productivity tool like Calendar, obviously.

It's also just a guideline, a suggestion, and if you think your app would benefit from having items fly in and out in all directions, if that's the feel you want to give your users, that's your choice. It's just probably not the right choice in most cases.

"Chaotic and fun" is how I would describe the feel. To me, the orderly one seems relatively boring.