Awesome eel !EELxu4rwJY No.480845
My head canon is that Luna is understands friendship better than celestia, she held against Discord alone once canon wise by using the elements of harmony without her sister as a 'complement'.
She has shown loyalty to her sister by forgiving her cold and almost traitorous treatment of her cruel banishment.
She has shown laughter *mostly comic*, she know she isn't the best a comedy but she always tries to improve and that should count. Huzzah the fun as been double !
She has shown kindness, as she truly care about her citizen, there were many episodes in which she was trying to improve her relationship to her subject. going way out of her comfort zone.
Generosity, she spend time and effort to help the CMC in two episodes in their dreamland.
Magic, she seems the solitary type but she always have love and concern in her hearth.
The only part of friendship she doesn't understand is honesty, since she isn't honest with herself, given how she got corrupted by the 'nightmare' essence growing her annoyance to straight jealousy. She failed to acknowledge that and the bitterness grew over time.
Celestia honestly lacked kindness and banished Luna for it. I guess people are afraid of the crazy and can't cope with it. She needed her but she turned her back and took the easy path she knew would work, banishing her own freaking sister to a tormentor seclusion. She isn't that honest either, always keeping stuff cryptic and all. Good thing we don't know more about Celestia, I have a feeling there was more to it than what the back lore gives us.
Luna must have serious Iron Will to not have more permanent damage in her perception of reality.