I bet she was the best bully.
"Wow that's great Starlight Charmer. You've managed to get the most popular boy in town to give you his number. Too bad you're never gonna call it..."
"Cause here only the prettiest of princesses get the cutest of guys. You'll forget about him if you know what's good for you."
"Y-you can't force me not to see him!"
"Oh yeah? Then how about we meet in my...oval office..."
And then she gave that poor girl a swirly and shoved a tampon up her butt.
Starlight Charmer would commit suicide five weeks later, and Celestia wouldn't even remember.