all i ever see in this thread is I LUV LUNA!!!!!!!!!!!!!! EVEN THOUGH SHE ONLY HAS 2 LINES AND ONLY APPEARS FOR 12 SECONDS! I LUVVVVVVVVVVVVVVVVVVVVVV LUNA!
i would like to know why everyone loves her.
Because you can turn characters like that into basically anything.
Imagine all the ponies being made of clay, all of the mane six being hardened statues, their personality, mannerisms etc. being already defined. Imagine the side-side characters, Octavia, Vinyl, Luna etc. being balls of wet clay. They have basically no lines and no mannerisms so you can turn them into whatever you want. That's why the side characters get so much attention.