We all have encountered NPCs rather essential or not that we came to hate, whats your most hated NPCs?

Njada from the Companions is one of mine, everytime i walk by her she makes a remark, cant tell you how many times its resulted in her being beaten to death and stuffed in a closet lol. Harkon is another one i hate.

That's kind of an alarming indication.

Heimskr. Michael Gough's over-acting makes an unbearable character even more unbearable.

I've just done the draugr dungeon to get the final word for storm call, the girl who guides you through it is annoying. She stands too close so that in a narrow passage she blocks your path.

my niece says Maven Blackbriar reminds her of my sister lol

Blasphemous! Anska is not nearly as annoying as Barbas

Barbas is the most annoying NPC in Skyrim.

Talsgar the Wanderer. He's forever showing up out of nowhere, running in front of me and getting his dumb butt hit, then attacking me for hitting him. Aside from the fact that his singing svcks, is overpriced, and he's killed three or more of my characters, I'm going to see to it that he never survives another encounter with one of my characters.

http://img.photobucket.com/albums/v218/neildarkstar/TESV%202015-05-14%2002-09-25-56_zpsgaib6gjv.jpg is how he finished his most recent performance...

Sven is another one like that, i had him as a follower once and went into this dungeon filled with falmor, im trying to sneak up behind one so i can take it ut with my dagger when out of nowhere he starts pounding on his drums and begins singing, im like you stupid idiot! being a werewolf i had no choice but to wolfout and battle a legion of falmor.

Delphine.

At first she was cool but once she acted like she was in charge and bossed the Dragonborn around, I had it with her and her stinkin' "crew"

She always irritates me when she pops up in the Bannered Mare, saying "Not here! I TOLD you to meet me in Riverwood!"

not to mention what she demands you do later in the game or else she wont be your buddy anymore lol

Nazeem tops the list. It's obvious why.
Dirge from the thieves guild, with his smart ass remarks.

Ditto.

I like Soul Trapping him and then using that gem to enchant a pair of boots, which I find entertaining ways to use them...sometimes I'll wear them as I walk through the Cloud District, sometimes I'll wear them when travelling through a swamp, other times I'll give them an Orc who does a lot of walking....

https://www.youtube.com/watch?v=3AgrrWsz1dg

You do realize that's the whole point of the character... http://en.wiktionary.org/wiki/heimskur.

that big ork in Cidhna Mine - I hated him, don't know why but I am really happy that I saw him just for one misson

And also Nazeem this @!#$ made ma angry so many times...

Yes, exactly, those two came to mind when I heard the question.

If I had any talent with the toolset, I'd make an addon where I can tell Dirge, "You realize I've taken down dragons with my voice, right?" and he'd whimper and run off and wet his loin cloth.

And for Nazeem, a quest where I can bankrupt his farm and steal his wife from him, plus get him banned from the cloud district, lol.

Awesome!

"....and lolligagging." He's always made me laugh.

Barbas is up near the top of the list for me, because of which, Lod never gets a visit from me.

Delphine, most aggravating essential NPC in game.

You can walk right past her without activating the quest and do the dungeon solo, she'll pop in at the end so you can activate and complete the quest at the same time.

When does that happen? She annoys me most when you meet her in her basemant and the dialogue options end up with her saying something like "you'll be back, you HAVE to". The first time I did that I almost abandoned the quest because of her attitude.

Likely the most annoying character in any of the TES games.

How many times has he pushed me off a cliff. I usually always avoid the area were he his and go around in a big round circle.

That's freakin genius!
I usually just reanimate his dead corpse and watch it turn to a pile of dust.

She seems to say that, if you see her in Whiterun, before starting Diplomatic Immunity, I believe. I spotted her there on a recent character, and had the thought "What are YOU doing here?"

Honestly, she does annoy me, though. I recently talked to her after the completion of the main quest(just before dealing with the OTHER issue), and I swear that something she said there, for some reason, suggest that she views the PC as a subordinate. Uh, no, sorry Delphine, that is NOT the way this works. Drei ni fus, BAH!.

And I have found a good reason to NOT play the Dawnguard side of the DLC. Why? It. That is all.

Children by a landslide, annoying little creatures.

No one mentioned Braith? Really? I would dearly love to make HER into a pair of boots.....

Oddly enough, the NPC that annoys me the most is Mjoll in Riften. One time after fetching back her lost sword Grimsever, I made the mistake of having her become a Follower. The lady never shuts up. One anecdote after another, endlessly. I'm trying to sneak up on some bandit camp and she launches into, "This reminds me of the time...." Made me wish umpteen times that they had a "Be quiet!" command that the PC could use on his Followers. What makes it odd is that I like Mjoll's attitudes: I'm every bit as anti-Thieves Guild as she is. But I really wish she would come down with laryngitis, frequently.