Silver for doing completely nothing.

Prince Blueblood for the sh***y way he treated Rarity in "Best Night Ever" although I never watched it. I know because of other bronies saying how despicable he is.

Rainbow Dash cuz she's a braggart, Pinkie cuz she's annoying and one time in Luna Eclipsed she is not considerate of Luna's feelings, and Fluttershy cuz...... and Celestia cuz she does nothing and is a mary sue.

^One, Pinkie isn't annoying on purpose. Sure, there's Fili Vanilli, but let's just say that's the writer's fault. And really, you can't provide a full explanation for why you don't like Fluttershy? Last, Celestia had to protect her kingdom for 1000 years. Alone. Without her sister. And she clearly got easily defeated in A Canterlot Wedding, so no, she is not a Mary Sue. You know, it's not very wise to add half of the Mane 6 (who are my 3 favorites) on your least favorite list
Now, my least favorites. Applejack. Why? Bats. I don't hate her as a character, she does hard work to protect the farm. But, in this episode, she was treating Fluttershy like a b***h. Fluttershy was only trying to help.

Rainbow Dash, she's waaaaay too cocky. Sure, she's tuned down a little in the newest ones, but still... I can't STAND people like that! (I sorta hate Black Star from Soul Eater)

And Pinkie's AWESOME!!!!!

@SkyheartPegasus I have some rejects to why AJ is your lest favorite. The bats were destroying her farm. You know where she lives and have her business. And those two stuff is important to her and having fruit bats destroy everything that she knew. To her it'll be hard letting go of something like that or for any pony/person in that matter. And Fluttershy taking the bats side is kinda of confusing to her the reason why she hates the bats is the same reason she didn't like Fluttershy taking the bats side on destroying her farm. She didn't listen to Fluttershy with her stubborn attitude getting in the way. She was only think everything she knew and loved was going to be destroyed by the bats. Even through I can see where you are coming from. And to be honest I had the weakest reason for hating Silver. It's just AJ had a reason for treating Fluttershy that way.

I don't like Rarity really, i'm not a big fan of people like that, being a tom boy and all

@PeacefulCritic I know all of that, I did say she went through years of hard work to get to the state of today. I have no idea on how she lured all 4 of the rest of the Six into her side, though. Dash, for obvious cider reasons, Rarity cause of her feminism, I guess Pinkie is just being Pinkie, and I have no idea how Twilight got into this. Really, did she trade her brain for her wings?

^Than why did you say she was treating Fluttershy bad? She was pretty nice to her most of the episode she just didn't listen to her when she was saying how it could be a good change but again her stubborn nature got away that away from that. Why I think Twilight agreed to it is because she was being selfless and was thinking of AJ's farm and how her business is getting destroyed. And near the end she did think of an idea. To help both sides. But again it didn't really work.But I do think she got dumber since she got the princess. When I think about it. she has been acting very dumb since she got those wings. You might have been on to something.

Fluttershy, because she doesn't have a lot of character development so far, she can still improve though. It's hard for me to hate anypony, except Diamond Tiara and Prince Blueblood.

Diamond Tiara and Queen Chrysalis. Ugh. Hate them both!

Not the hugest applejack fan, but probably Diamond Tiara.
I hate diamond tiara because she's pointlessly a bully and a fucktard.
Applejack is stagnant and boring. Her character has no way to develop so any story where she's a main character is boring as hell, perhaps leaving out Applebuck Season.

I think my least favourite is Silver Spoon. While I like a lot of antagonist characters on the show, I've always found the "snobby popular girl" stereotype to be distasteful and somewhat offensive (despite never being popular myself). On the rare occasion I have started to like individual characters who fall into this stereotype, if they are given an in-depth backstory as to how they act the way they do (e.g. sometimes a character is like this due to neglect and because their parents never taught them how to be considerate, and later their character begins to develop when they start to let themselves become friends with nicer characters). What bothers me with Silver Spoon though is that she just comes across as arrogant so she can "fit in" with Diamond Tiara, who seems to be the ringleader of the two. While I dislike Diamond Tiara for many of the same reasons, Silver Spoon gets to me more, somehow. I suppose it's because she is a mix of both a snobby rich girl stereotype, and someone who does not make their own decision (as I said, Diamond Tiara seems to be the leader while Silver Spoon is the follower).

I was surprised that this show had characters like that, as the majority of characters in this series are written in a more realistic nature with depth to explain some of their behaviour (e.g. Babs Seed; even though bullying of any kind is wrong, we at least found out why she acted that way and her character had more depth than the other kid bullies). Fortunately, there is a good range of characters on the show in general, most of which I love and find empowering rather than offensive. The worst thing is when a TV show uses "The Smurfette Principle" (an almost all male cast with only one female) and the only female character is stereotypically superficial and shallow. In this show, at least there are lots of female characters and they have a diverse range of personalities.

Discord. He annoys me a lot. He's also a terrible villain.

I hate Tirek. No questions asked.