...I've re-read what I've written, and I've sort of lifted off the top of my head a little with this response: so, there's autism of a personal, wall-o-text nature here. If that's not your cup of tea, then by all means filter the two posts that I'm spreading this across. I know I'd be tempted to.
First, here are two basic assumptions: one, by default, Celestia loves her ponies. They are more to her than her world; she banished her sister, her only only family, to the moon for a thousand years, rather than risk harm coming to her ponies. Her ponies *are* her world. Two, my Celestia is 'confident, wise, gently-aloof mentor figure' Celestia; Lauren's Celestia.
There's a whole lot of reasons as to why Celestia is my favourite pony, and I probably couldn't adequately express them in text without losing some of their flavour, or meaning. However: I adore their storybook world, which operates per the laws of 'would it make sense to a small child in the target audience'. Celestia is the perfect guardian of such a world. She knows, along with her sister, that they are fictional characters, and despite this chooses to watch over and protect their world regardless. Therefore, to love Celestia would mean to love her ponies as well: one couldn't be without the other.