i fell off of mlp:fim in season 2 (not because of anything in the show, just because watching things sucks and i'd seen enough) but my understanding is that later in the series, the entire mane six gets assigned "writing letters to celestia" homework

and i'm also led to believe that there's an applejack-focused episode where she basically gets to write "dear princess celestia. i didn't learn shit! i was right the whole time!" and that's awesome. i love that for you applejack