Huh? I don't think that I understand this. But I'm pretty sure that there are way more examples of her and the knowledge of friendship than her ruining friendships. After all..
-In Amending Fences, Twilight went out and made up with her old friends. She never gave up on Moondancer.
-In the first Equestria Girls, Twilight reunited the Humane 5 and there's a chain reaction that leads to the school coming together rather than being divided
-Twilight technically is the one to discover the magic of friendship
-When Discord was evil and used his magic to turn the rest of Mane 6 into their "element of disharmony", she had never given up on them.
-She sacrificed all the alicorn Magic for them in the season 4 finale
There's more to list though