…it seems Celestia's extrovertive and Luna's introvertive personalities may be a product of their raising. Celestia got a lot of attention and adoration for raising the sun.
Hmm. I have to say, interesting theory, jolly good old chap!. Of course, given canon, Celestia was kind-of loved more than Luna, or atleast, had a bloody big amount of attention because of her special talent in comparison to Luna. This would further lead to Nightmare Bun but we are not talking about it ATM.
She's well adapted to being around others and a millenia is a long time to master etiquette and social skills. And being a ruler requires forming and maintaining diplomatic relationships.
Given your earlier theory as an viable variable, it would be easy to point out that the attention Celestia received was a crucial point in learning social skills. Meanwhile, Luna had it though with friends, so she became an introvert. Although let me point something good sir; Diplomatic Relationships are, sadly, diplomatic, and, although she wouldn't be technically lonely, that relationship cannot advance further than that. It's unclear how Celestia would manage the crown and the diplomatic relationships, but, by the slightly noticeable hints, Celestia is, pretty much, an slave to PR, a woman wearing the queen mask I dare to say, and, as such, I highly doubt diplomatic relationships could advance further. (Combine that with the general non-acceptance of other races about friendship stuff). And that's the issue I point out and you understand:
She's probably felt alone, but never been truly alone for any meaningful length of time
Felt indeed, she couldn't be alone because she wasn't alone. But she felt indeed alone without anyone to chat or share a cup of
tea. But given that she wont dare to show out her frustration or weariness, she played along… for 1000 years… while Luna, (The only pony that made her feel company) was a Nightmare Bun stuck on the Moon. That may have done some small stuff on her psyche. Since the whole point of A Royal Trouble it's a poor communication kill, they're so engrossed on their royal duties 24/7 that they rarely have any time to talk about their day, which would explain why they're so eager to blame. Now take Luna out of the equation; she had to practically do double job until her sister returns (Because I don't think that without her help Equestria would have advanced from the terror of a Nightmare Bun roaming around in the nightmares of people). And also she lost Luna to talk to, so she was alone in power. That strain of an naturally friendly an extrovert Celestia thay can't talk to ppl probably left a mark, until Twilight Sparkle appeared to save the day (And proved on Celestial Advice; she kept Twilight longer than neccesary to have some company, and when she sent her off to Ponyville it was when Luna returned to her).
…but never been truly alone for any meaningful length of time until A Royal Problem. Talking to herself was probably a defense mechanism from an unknown fear of loneliness. She's probably thought out loud to herself before and thought nothing of it because, after coming to a conclusion, probably had to act on whatever problem she was working through.
And that's the turning tide of the whole Barbarossa campaign: she most likely felt alone at the period bewteen Luna colonizing moon and Twilight coming to her rescue. She wasn't alone. But, an epically extrovert person like her will slowly drift to insanity when they feel alone (And it's entirely possible that she talked to herself as a defense mechanism during that period). It was a monumental effort to take care of a diarchy as one without anyone to talk to, she basically had a face of "Please hug me and chat with me pls, I'm an extrovert unable to be an extrovert". Twilight came, now she had someond to talk, Luna came, Twily left, well, she had Luna. She could also talk to Starlight. But now Starlight's asleep, Twilight it's not present and Luna it's also asleep from wearing Celestia's queenly mask. There, at that point, at that exact point her brain gone "I'm alone again!? Oh hell no!" and unknowingly she returned back to talking to herself to "avoid loneliness"
There, our theories join and we find the purpose of life mi amigo, it was a defense mechanism, coming from an point where she felt truly lonely. And we stand together as one on our point that, while Celestia is probably the most normal of the diarchy, she has a relatively small amount of psychological troubles stemming from her time feeling alone. And her talking to herself it's a defense mechanism from that. Because she, as an extrovert, never liked to be alone or feel alone.
…Oh bollocks, bloody Asperger. .. either way, I agree with you in most of the points exposed. If you want you can reply your opinion our point out something, have a nice day/night!
(And sorry if it's nonsensical, it's 3:30 AM in here) @Background Pony #B006
JAJAJAJA, C MA MO. I've seen it before, but you reminding it to me made me break from laughter. Jajajaja! She's losing the plot right there.
"This it's my night bitch"