Zoe wasn't planning on going anywhere but it was cold and she liked Greed grabbing on to her like that.. because it just meant he wasn't planning on going anywhere either. "Well.. for mortals it helps you count how many years you've been alive but more than that it's a celebration for your loved ones and friends to just be like yay you're alive! To be thankful for you and that day is special because it marks when you came into the world and if it wasn't for that day then all these people wouldn't have you in their life. Plus you get cake and presents so you'd love it."