EDIT : Sorry, I meant the title to say Star Trek not STO 
There is a lot I love about Star Trek.
But there are a few characters that really-really get under my skin.
Wesley Crusher is no doubt the first that comes to mind. But what about the others?
List yours here

... I will start
Comments
My vote goes to Dr. Pulaski from TNG or Lwaxana Troi. Any time either of them were on screen I fought the urge to turn off the TV and it was even worse when the episodes were focused on them.
i guess neelix was slightly lovable from time to time.
keiko was just something to torment miles. when the pah-wraith invaded her body, her evil level actually went down.
so keiko.
Ughhhhh, this dog for sure! :mad:
Spock WORKED
the others pander to BAD genetics
Klingons and Humans are not from the same genetic base
in the actual game the most annoying NPC is that Ferengi in "treasure trading station"
I would have LOVED to stick a phaser up his nose
Neither are humans and Vulcans. Or Bajorans and Cardassians. Unless you subscribe to the whole Precurser/Preserver story about all humanoids being descended from a single race. Now Vulcans and Romulans...
In Trek - Leeta. Couldn't stand her whining.
In STO - Leeta again, along with Slaamek (the Reman gladiator/double agent from Coliseum).
Alexander
The little blond girl imaginary friend from that one episode of TNG. :::shudders:::
Keiko, definitely
Years later, I've gotten past that and found Odo to be a pretty fascinating character. I just rewatched most of season 1 of DS9 and Odo had a lot more going on than I ever noticed back in the day. Turns out Bashir and Dax were pretty annoying in season 1. Heh. Bashir got infinitely more enjoyable I think after the time travel episode with him and Sisko going back to the race riots. And Dax just finally got more to do than be chased after by all the cast like it was in season 1.
Mirror Kira. Yes I get it... She loves herself. I don't need that image in my brain. One which requires a knitting needle to remove.
Keiko. I see her lips move but all I hear is "blablablablablablablablablabla".
Kai Winn
That would be Season 5, Episode 22, "Imaginary Freind", as the caracter "Isabella" played by Shay Astar.
1. Kai Wynn
2. Mayweather
3. Kess
I always felt Rom and Nog to be the most annoying ones.
just didnt like any of them epecially picard more then the others, i just think hes a little too sure of himself and having pulaski, vash and lwaxana get him off his high horse is when i can actually like the man.
the female shapeshifter its all believing her own rubbish instead of getting into the game and making her own distrust look like something, she has her minions do it. that voice is also very annoying after a while.
dukat which is obvious, just another swaggering gul with too much vanity and not enough ability.
kirk just because he keeps getting into too much cowboy diplomacy instead of showing some restraint.
mccoy,' he's dead jim', but so is his acting career, he goes way over the top on some instances, almost insufferable in a sense.
Romulan and Vulcan ARE the same race
Vulcan/human they got away with once (Spock) as a highly unlikely event but once you can stand
but by Voyager
does no one date their own species??
I actually LOVED Kai Winn as a character! I hated her, but that's why I loved the character. She was such a complex villain!
Dr. Sevrin and his entire motley crew.
Mr. Adventure.
Admiral Cartwright.
Elaan (gorgeous, but annoying).
..that's just a few I can think of at the moment.
His writer should be shot in the hand and never allowed to work again. (Not literally only metaphorically.)
1. Neelix- Look everyone Jar-Jar learned to cook!
2. Wesley- Shutup Wesley!
3. Chakotay- My native american sense are tingling! It's sad that he had no real character beyond that.
4. Kes- Voyager got better by a lot without her.
5. The Bio-Neural Gelpack- It pretty much was a character in season 1
6. Deanna Troi- I still burst out in laughter when I see her flying in the green cloud thing
7. Kira Nerys- she got better in the last season, but other than that I couldn't really stand her
8. Ezri Dax- No really, you replaced Jadzia with a twelve year old?
9. Guinan- Whoopi Goldberg is overrated
10. Any character on any Trek in the first season- No Star Trek series had a good first season in my opinion. They all got better by differing degrees after that.
And I really don´t understand why people would hate the Bajorans so much. After 60 years of opression, violence and murder, one certainly is entitled to not be overjoyed by it. The whole situation with the Bajorans and the Cardassians made for some of the most interesting story arcs and character portrayals.
This! Infinite times over! I took so much pleasure in the episode where Tuvok ran a holodeck program where he would choke Neelix to death. So much so that I would replay the scene over and over. By far the worst character ever envisioned.
If no one here has heard of SF Debris you should look it up as this guy has the same hatred of Neelix as I do. When he does reviews of Voyager episodes he has a section at the end he dubs "Stupid Neelix Moment".
Gosh, thinking about how much I dislike this character gets me worked up! lol!
Spot was an incredibly well-developed character, we learned about her interactions with Worf, her progressing dietary exploration (She had several replicator programs specifically for her!) and served as a great anchor for Data's Character.
Porthos, on the other hand was a melodramatic toolbag.