Most annoying thing in any video game?

[Pm0n3y]

the "marked man" events in burnout paradise
the first few levels were fun, but after awhile they wouldn't even let me respawn. then it got annoying.

 

[Mad Maniac with axe-firing chainsaw]

I'd have to go with hitting "that one boss" or otherwise encountering an area which takes a billion tries to get past or simply requires co-op. Game destroying glitches are another infuriation, though I've been mostly spared these problems. (except for in Fable 2 where my dog occasionally refuses to search for buried items in new games, meaning I have to restart the game. Thankfully once he starts searching he never stops.) Finally, while I like RPG's I don't particularly care for grinding, especially if its forced grinding.

 

[MiracleOfSound]

"Please sir, can you spare a few coins? Just a few coins, that's all I'm asking... I'm poor and sick and hungry..."

I'm grinding my teeth just thinking about it.

'Thank you, kind sir'... CRASH

reboot

Edit: I jus realised that's from Assasin's Creed, not Oblivion. You're right though, those beggars were godawful.

 

[J-Alfred]

the "Final Fantasy Effect". that is:

-going to a lvl. 10 dungeon when you're lvl. 8
-building up experience until you're lvl. 10
-defeating the boss in the dungeon and being sent to the next dungeon
-finding out the next dungeon has monsters at lvl. 25
-dying a lot. a whole, whole lot.

this is also referred to as the "Dragon Warrior Effect", the "Golden Sun Effect", and the "Tales of Phantasia Effect".

 

[Gardenclaw]

Massively long unskippable cutscenes just before a part in a game that is hard and you are likely to die in, So you end up sitting through the same cutscene numerous times.
Time limits in games that are out of character with the rest of the game and just seem to be thrown in to be a total pain in the arse.