@Background Pony #D3A6  
https://i.kym-cdn.com/photos/images/original/000/345/619/45d

@Beau Skunky  
Good girl. Now go play, but be nice, okay?

@s617519  

@Beau Skunky  
Aww, I can’t say no to that face. OK. I’m sorry too. Just don’t ever do it again, okay?

@Beau Skunky  
Sorry.

@Red-Supernova  

@Beau Skunky  
Nope. I’m never letting that go.

@s617519  
@Red-Supernova  

@Beau Skunky  
Sorry but after the manipulative shit she pulled in that episode, she doesn’t get a free pass.

@Beau Skunky  
Hey, don’t look at me like that. I know you’re upset, but, of all the possible reasons for you to maybe even make that face… This one’s on you.

@s617519  

Serves you right, you little stupid, jerky, annoying brat.

@Background Pony #C2D2  
She’s not mean anymore, her mom is the reason she was mean, she’s reformed and nice now

Actually, while I haven’t seen this episode yet (or any, why am I even here?) from what I have seen, bar this one scene she was constantly happy and/or highly irritable, highly productive, feeling like queen of the world, and making poor decisions even by her own standards, and yet was still able to function normally; all of which are in the list of symptoms of Hypomania.  
Furthermore, she has some unexplained prolonged absences in several CMC episodes, which while having no canon explanation, could be possibly explained by depression. If this is true, it seems she has Bipolar Disorder, specifically Type II. If this was the case it’d be fascinating for all. We’d have a rare case of childhood Bipolar Disorder in fiction and a possible explanation for (some of) her behavior to boot.  
Also, in my headcanon she’s a “comfort eater”, and is actually kinda chubby.

“You are here by stripped of your title and you also received two months of detention!”

Y’know, even if she is a li’l bitch, (the newest episode sure increased the Tiara-hate) with that sad adorable expression, I can’t help, but think “d’aaawwww…” Why do these ponies have to be so cute?
 
@The Twelfth Doctor Whoof  
Y’mean “Chubby Diamond Tiara?” That’s surprisingly popular, even with people who don’t like fat ponies.

“This courtroom finds you guilty.”

@Background Pony #42FB  
I hate canon DT just as much as everyone else, but I like her alternate-universe tumblr counterpart who put on 6+stone and became a lot nicer as a result of being a fatass.
 
@Red-Supernova  
She apparently suffers that so-called affliction common to rich bitches like her: “Affluenza”. One symptom is that sufferers are never punished for anything they do wrong.

You’d think after this episode, Diamond Tiara would finally learn that being an enormous, manipulative, self-centered, stubborn, and troublemaking brat would always result in her getting her comeuppance.  
The CMC really need to inform Cheerilee or the Mane Six about Diamond Tiara’s behavior.

We all hate you. Everypony fucking hates you.

“Put on the cone of shame!”