Sure Diamond Tiara can be a bully at times, but it's not like she ever says anything that's untrue. Even if what she says it's mean she doesn't lie. It's like calling the fat kid fat, or calling the dumb kid dumb. Or in this case pointing out the little geeky girl's every flaw to the point where she has no self-esteem at all.
Who cares who she picks on? Twist, the CMC, even her best friend Silverspoon. She's completely justified and unapologetic in telling them all the truth.
But as morally righteous she may see herself, not everypony thinks the same way. Even the ones who did may eventually start to get annoyed with her. Especially when she says something just a little too harsh even for her.

New chapter every Saturday! Complete!

Proof read by The11thWonder

This is a spiritual prequel to Happy Anniversary Sug. It's based on a little sub/back story originally just brushed over in H.A.S. but not with the same exact back story.