At first this looked to me like just another "be yourself" episode, but I think it is more interesting to look at how it was the environment that determined whether Discord was present or fading. He tried to adapt and fit into something not him and started fading. Someone else, a friend, Fluttershy, brought the environment back to nourishing him where he couldn't do it by himself anymore.
I.e. sometimes we need others to lovingly do for us what we cannot do ourselves, to add a perception of us that we may have lost, and that might require tangible means, as shown in the episode when Fluttershy's words didn't make a difference. Words are about minds arguing, and in that game, if the problem is in the mind, the problem will always win. As was shown by Discord just countering any of her suggestions with words.
Generally, the episode couldn't possibly have been a downer for me because, as I like to say, "There is no such thing as a bad Fluttershy episode." <3 <3
P.S.: I was a bit disappointed to not see the words "Judgy Clerk Pony" in the credits.
Oh well, TO ACTION! ^^