When I couldn’t see a future, and I was afraid… when the future was clear, and it hurt to see… I’d just close my eyes, and lose myself in happier days.
Oerba Dia Vanille, Final Fantasy XIII

With their upcoming confrontation with Discord looming, Celestia decides to lose herself in happier days; to remember the good times she used to have, and wonder where everything went wrong.

Warning: headcanons inbound.