Come up with a really bad moral.

[SBaby 660]

Dear Princess Celestia:

 

Today I learned an important lesson.  You should never put mustard on the cat.  Not only will it take a long time to wash off, but she might gouge your eyes out, or injure you in other ways.

[Not_active 732]

Dear Princess Celestia,

 

Today I learned that I should run campaigns to ban everything that offends me. I don't want things I don't like on a personal level to be legal. I don't like when people do things that I think are weird which affect nobody but themselves. Nobody should be able to offend me again, offending me should be illegal.

[Paradoxy 12]

 

*Shudder.*

 

Dear Princess Celestia,

 

Today I learned that it's okay to obliterate innocent ponies without giving even a moment's pause to consider the fact that they are sentient, self-aware beings, as long as their existence is extraneous and nopony will miss them. More importantly, I have come to appreciate that being the most powerful pony in the room means being the arbiter of who is allowed to exist.

 

Your faithful student, Twilight Sparkle.

[Scrubbed user 3,416]

Dear Princess Sunbutt

 

Today, I learned that it's a bad idea to vigorously rub sandpaper on certain parts of your body.

 

Your loyal subject

 

Indigo Racing

 

P.S. I did get $20 out of it though.

[Twireadbok 142]

Dear Princess Celestia, today I have learned that it is best to get rid of useless things. That is why I have killed Spike.

 

Your Faithful Student, Twilight Sparkle 

 

https://www.youtube.com/watch?v=xYP3xI-dGl8

[Omega Centauri 316]

Dear Princess Celestia,

 

Today I learned not to walk through the ghetto when I'm dressed up as a ghost for Halloween.

[Castle Bleck 19,330]

Dear Princess Celestia,

 

Crystals... Slaves...

 

Your Faithful Tyrant,

King Sombra

Edited March 3, 2022 by Even Evil Has Standards

[Giygas 40]

Dear Princess Celestia:

 

I tell kids to brush their teeth twice a day, but I really brush them only once. I don't floss either.

 

Your faithful dentist,

Dr. Rabbit

[Solid 1,327]

Dear Princess Celestia,

 

qwertyuiopasdfghjklzxcvbnm

 

Your faithful student,

Twilight Sparkle

[Chatterbox 25]

Dear Princess Celestia,

 

I just wasted your time with this utterly pointless letter.

Don't worry though, I wasted even more of Spike's

 

Your faithful student,

Twilight (Not the rubbish book).

[An Unknown Pony. 370]

Dear Princess Celestia,

 

What If I Told You That I Decided To Rule Equestria By Killing Everypony In Sight(Including You),Then I'll just steal one of Zecora's Potions and Revive Them And Process Every One Of Them

 

Your 'Mad Scientist' Student,

Twillight "Sparkle" Mengele

[Silverhoof 2,844]

Dear Princess Celestia,

Your animals at the palace won't love me. So I killed the ingrates.

PS. Don't look in your garden.

 

Your faithful friend, Fluttershy. You are my friend, right? You love me right? Right?

[Scootaloo9074090 501]

Dear Princess, Celestia,

 

Today I learned that after causing multiversal genocide on countless world to spread the magic of friendship.

Sincerely, your murderous Faithful Student Rainbow dash.

 

 

Edited February 21, 2022 by Scootaloo9074090

[Sparklefan1234 169,813]

Dearest Sister,

Today We learned that daring another pony to eat an entire jar of peppers all at once will burn them in the end. 

Warmest regards, Princess Luna 

Edited March 2, 2022 by Sparklefan1234

[Sonic Shimmer 4,131]

Dear Princess Celestia

Today I learned that absolute monarchy is an outdated and repressive form of government.

Today the revolution begins.

Love Twilight Sparkle

[Theautisticrebel 304]

Dear Princess Celestia

I learned that it's okay to have a literal child be sent to eternal damnation if they are a brat.

Love Twilight Sparkle.

Edited September 4, 2023 by Theautisticrebel

[Antiyonder 1,102]

I will take a page from Homer J. Simpson:

Quote

Young man, since you broke Grandpa's teeth, then he gets to break yours.