Every character you have to escort in a game. Those guys suck. The dumb AI on top of all the enimies, kill me...

Besides Navi, I'd say Wiki from the Wii's Zack and Wiki. Wiki would make the same annoying noises and would just stare at you as you're about to die or make some rude remark. Useful at times, but I think it's the constant lack of speaking and just making noises instead that grated on my nerves.
And as for the red boat in Wind Waker, I couldn't stand him either!

1)Every Character to ever star in "Escort Missions".

2)Dynasty Warriors ..."The Base".."That Base"..."Your Base"..."Our Base"..."Their Base".
....................Base, Base, Base.

3)Navi can not be jarred. I have tried countless times.

4) Cheap A.I. or Difficulty ...In fighting games they are easy to find. An example that I still dislike even after I have mastered beating them is...The Chick in Gold Armour that Fights like Taki in Soul Calibur 4's Tower of Lost Souls Battle on Floor 45. (You can beat that floor only with the Leviathan or Voodoo Armour. Witch is unlocked by..... "Achievements"???. You have to look it up on-line to find even the slightest answer???.)

5)Every character that gives Odd advice or Clues that do not help. (An example of this is Zelda 2 or Castlevania 2 For the N.E.S.)

Good Luck.
Peace.

Peach, especially if you play any Nintendo games. Especially Mario Party. "Haha! Did I win?" NOBODY CARES PEACH.

That annoying Mecha Chao from Sonic games. GOOD LORD IT WAS THE MOST ANNOYING THING EVER.

I'm pretty sure millions of people can agree with me that Navi is the MOST annoying character ever.

Princess Peach is annoying because she's always kidnapped by Bowser! 

I would have to go with Sheva from Resident Evil 5, I was going to put Fii from Skyward Sword because I think she is the most annoying sidekick. But the I realized that while she was annoying, she only pops up to give advice. Sheva on the other hand affects the game play, and she is probably one of the worst A.I characters ever, and she is your partner too. She wastes ammo, she gets stuck a lot, she heals you when you have 10% of your health gone, but doesn't heal you when you are almost dead. Most of the other characters mentioned only have annoying personality, or only effect for a short time. So Sheva is pretty much like one big escort mission.   

Princess from little lamplight.
She is from fallout 3 and she is so annoying.

navi from lengend of zelda ocarina of time

In my opinion, the most annoying character is Scott from the henna Pokémon games. The guy is so annoying, appearing out of nowhere every time.

Some time is navi

Vyers, mid-boss, the dark Adonis or whatever you want to call him was the most anoying for me (hes from disgaea if you do not know -w-) every battle with him over stupid-ness and the way he acts just annoys me, i do think hes a good character though, hes just annoying

Navi really wasn't that bad. Just a tad loud for most people. But he isn't really bad once you are used to it. So can we ease the hate navi gets just a little bit?

What about Vanilla, from Final Fantasy XIII? There's a reason I'm not fond of anime, and that's because of sugary, high-pitch-voiced 'lalala' girls. Gosh, just shut up already.

Brucie from GTA IV deserves to be on this list. While he has his likable traits, he's that person who always shows off, making out like he's some elite, while he's really just very insecure.

Blue from the first generation Pokémon games was an annoying prick. He is more likable than Silver from the second generation, but Silver wasn't so much annoying as just being a plain prick.

Barry, from Alan Wake. Supposedly the 'comic relief' character. But eh... he's not very comical.

I'll add Navi from Ocarina of Time to my list. I told my TV to shut up
more than once while playing Ocarina of Time. And I had my volume on 0.

Tidus, from Final Fantasy X. This hurts my heart. I really liked his optimism and his spirit. But his English voice actor... Oh gosh.

Baird, from Gears of War. I disliked him, for some reason. Perhaps it was his cockiness.