I love the idea that big Macintosh has a thing for Princess Celestia (lots of ponies do, but it's wise not to be outspoken about in in the fear of offending the princess).
So I had a dorky little idea that Celestia comes over to Applosa to take part in a celebration held by the buffalo tribe (whom in my headcanon she befriended their first leader) and the Apple Family stop by for a visit, marking the first time a lot of AJ's family has met her in person. Big Mac of course dressed his best and is his most talkative.
Chances are Celestia either doesn't notice or she's used to it and is no more than touched by this kind of behavior from stallions. After all, Big Macintosh is a little 1000+ younger for her liking.
That doesn't stop some people from getting competitive needless to say: [link]