QTE's. Enough is enough
Crap DLC like charging for costumes. As I said before Maps/Missions/etc I am fine with if the original game was loaded

DLC is the biggest scam that ever existed in the industry.

I agree with you. I liked it when RPG's gave you the option to do either.

I think for me its forcing co-op into a game that does not need it just for the sake of having Co-op.

Shoehorned-in multiplayer modes. Not everything has to have multiplayer, damn it.

Paying for DLC.

Like most have said, overpriced DLC.
Also, exclusive DLC, it limits DLC sales and really isn't going to push sales of a console... it just pisses off the rest of your fan-base.
Finally, Secu-ROM and other restrictive anti-piracy measures.

DLC

im going with quick time events

Paying for content (I don't remember doing that on the PC in ages, cept for Expansions of course).

Releasing games when they are not done (Just effing delay the game, no one gives a fuck, look at Blizzard and Valve, they don't give a fuck when the game releases they just finish it)

Releasing buggy games (come on now.... that was the ONLY benefit of console games and now it's gone the moment patching is allowed....)

DRM (useless, that's all I can say)

Shoehorning PC genres on Consoles and vice versa (Halo Wars, FPS games, Street Fighter 4 I'm looking at you)