Princess Twilight Sparkle, or so she's titled as, simply hasn't felt much like one. She's respected as a princess, greeted politely as a princess, but unlike Celestia, Luna, or Cadance, hasn't had any duties of one.

Caught in-between her expectations of the life she'd lead and the life she's actually leading, who could blame her when she feels like a zombie? Speaking of which...

Credit to WhiteEyedCat for the Appleloosa pic