Why is Everything About You?

I spent most of today catching up on housework and playing with the kids.  Like most days I was exhausted by the early afternoon at which point Addison asked if we could go out to ice cream after dinner.  I said no and explained to her that David and I would be too tired at the end of the day but we could go this weekend.  She looked at me and said, "Why does everything have to be about you?"  Help me.