Fwelin 
[@spikeyboy](/images/3440369#comment_11013778)
Fostering friendship is not the same as attempting to meddle in peoples' personalities to improve them. She never actively attempts to make people less of a jerk (Trixie, Flim/Flam, Neighsay, every other single-episode jerk antagonist, etc.) because that's not her job.
Twilight almost certainly already knows why, but that doesn't help with this at all. Trixie would just lash out if Twilight tried to help.
Finally, the topic this post is about was resolved very quickly after Trixie became a recurring character. Trixie even admits in a later episode that she's no longer jealous of Twilight, and she isn't nearly as much of a jerk as she was in earlier seasons. Late-series Trixie is more naively insensitive than actively assholish, and Twilight doesn't treat her with her former suspicion.
Fostering friendship is not the same as attempting to meddle in peoples' personalities to improve them. She never actively attempts to make people less of a jerk (Trixie, Flim/Flam, Neighsay, every other single-episode jerk antagonist, etc.) because that's not her job.
Twilight almost certainly already knows why, but that doesn't help with this at all. Trixie would just lash out if Twilight tried to help.
Finally, the topic this post is about was resolved very quickly after Trixie became a recurring character. Trixie even admits in a later episode that she's no longer jealous of Twilight, and she isn't nearly as much of a jerk as she was in earlier seasons. Late-series Trixie is more naively insensitive than actively assholish, and Twilight doesn't treat her with her former suspicion.