What does it mean to be immortal? Celestia's memory is very old. It is twisted and confused. She wakes one night to find that she can no longer tell her memories and her dreams apart. She no longer knows what was real and what was only dreamed.
During the most violent storms, Pinkie runs outside and sits on the tallest hill in Ponyville. Everyone says she's "just being Pinkie". But she knows that by showing love for the storms, she shows love for the pony who makes them.
Rainbow Dash definitely didn't do anything wrong. Rarity is the one who's wrong. Rainbow Dash is absolutely, totally, a hundred percent sure of it. But then why did she just buy a wagon load of apology bouquets?
Prior to the events of A Canterlot Wedding, Princess Celestia asks Cadance what ought to be done with the changelings that have been discovered living hidden in Equestria. Cadance's ruthless response surprises her.