Ever since Smash Gamer showed up in Ponyville back in the day. Twilight, while confident that friendship is magic and that Smash would be able to understand where he was wrong. She did have nightmares and visions about what would have happened if Smash Gamer was able to rally a bunch of ponies up to confront her. Calling her out of her hypocritical ways of delivering friendship, giving those closest to her special treatment, while ignoring others, shutting down everyone who disagrees with her, performing actions that she would demonize others for (like reforming spells, doxing and indoctrinating young minds) and showing an absolute lack of empathy towards those who actually have suffered in their lives among many other things. Like with Cozy Glow who had been abused by her sociopathic parents and just wanted to have friends. Disregarding everything Smash has been through and called him a villian, just because he wanted revenge on her because she destroyed his life and almost destroying Starlight's friendship with Trixie just because Twilight didn't like her. Just because she has been Celestia's pet ever since she was a filly, joining in right after Celestia kicked off Sunset Shimmer simply because the later wasn't an exact carbon-copy of the former. Therefor Celestia banished Sunset to the EQG-universe and then lied to everyone in order to make Sunset look like a villian. So much so that even Sunset herself believed it after she was defeated.
Which was also the same way that Twilight convinced Starlight that she was evil, even though she along with Smash were trying to save ponies who had their lives ruined by Smash Gamer's parents. Then making sure that none of them would feel like an outsider by making all of them the same. The reason why Starlight didn't use the spell on herself was because if she did, she would be able to save the other ponies. Thus putting her own safety above everyone elses and thus feel like she didn't care about the others. She knew what monsters Smash Gamer's parents were, most notably his father, who killed everyone who he had problems with, including Pear Butter and Bright Mac. Whom he assumed were trying to adopt Smash Gamer into their family, when it was actually Suger Belle's parents who tried to do it. Who already had their lives destroyed by Smash's mother, because they didn't 100 % believe that mares were oppressed in Equestria.
There is much, much more to go over. But Twilight fears that she will never be able to really understand friendship. Considering that she did betray it already by stealing the pearl from Seaquestria.
Vector Credits:
Crystal Guard — frownfactory
Background — hampshireukbrony
Rarity, Applejack — cloudyglow
Limestone Pie — thebosscamacho
Lyra Heartstrings, Twilight Sparkle, Bon Bon — tardifice
Rainbow Dash, Sunset Shimmer — luckreza8
Fluttershy — jhayarr23
Smash Gamer — Pony Creator
Pinkie Pie — jeatz axl
Starlight Glimmer — davidsfire
Trixie Lulamoon — sonofaskywalker
Cozy Glow — illumnious