The problem with the whole "which pony are you" thing is that I identify with all six, in critical ways. For most of them its a technicality or a minor personality trait that makes it difficult to say I'm definitely most like that character and not the others.
Applejack: Not counting a little bit of obnoxious tomfoolery in the chatroom I'm generally an honest person and even frank if I have to be. I try to be reliable, even if it means going in over my head and I wind up pleasing nobody. I'm not too stubborn though, but I am very hard on myself.
Twilight: I do enjoy stories, learning, and building my skills. I can come off as introverted sometimes but I actively try to participate in social situations as long as they're not going to pose a problem. Although, while I have people telling me I'm talented all the time, I know better.
Rainbow Dash: I also have a little bit of spirit for adventure. Evidenced by my diving headfirst into a trip to Europe last year, and then exploring the city of Amsterdam alone (for the most part). My experiences in scouts also reflected the same thing, and I see my life at school as an opportunity for adventure. All the same, I don't do stupid or reckless things.
Rarity: Like Rarity I have an eye for aesthetics, and love to make and critique things. When I see that something's needed, if I have the opportunity, I like to offer my own skills. Now while I may be a little squeamish, that doesn't mean I'm afraid to get my hands dirty.
Fluttershy: I wouldn't say I'm very shy, when I do get comfortable in a social situation I'm very chatty and I've gotten very good at small talk. All the same I'm extremely polite. I can be very good-humored and sarcastic if I have to be, but there are times when I'm so busy being polite I miss a social cue somewhere. Additionally, I respect everyone I meet and care very much for many of my acquaintances.
Pinkie Pie: And when the time calls for it, I love to be random. I also am inclined to be a little eccentric. Even as I keep certain things such as tact and appropriate social behavior in mind, I still want to stand out from the crowd. That said, this is more how I am around friends that I am comfortable with.
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Now since personalities are diverse, this could just be me but I'm frankly curious if anyone else identifies with all of the main characters so equally... and why. It would make a lot of sense to say that each of the characters represents a different element of our personalities... but I know some are more aligned with Fluttershy, for example.
Since my personality is linked to all of them, the reason I choose Rarity and Twilight as the ones I am the most like is only because of Rarity's career (an artist) and Twilight's lifestyle match mine the most.