I really hate a game requiring online activation. I think it should be an option, sure, but to require it is ridiculous, and Steam having a monopoly in that market is a very bad sign. That's really my only problem.
I mean, I can pull out my DOS machines or Win 98 machines and just go play a game that I have. With Steam, it's not like that - if you buy, say, "Doom" on Steam, a title that runs in win95 and dos, you can't -play- it in win95 and dos, or even win98 or 2000, because steam ITSELF needs to be installed first, and the game needs to be launched through Steam. Steam will not install on those operating systems. Also Steam always wants to install visual C++ libraries, .net framework, etc, etc... Not a big fan of that extra Microsoft bloat, or even Steam's bloat. Something really nice about the old days was when I went to play a game, the game had access to pretty much all the hardware in my computer. Now Win7's GUI OS, Steam, shit tons of random services and 3rd-party software is running at the same time, and if I could have one less stupid IM client with a shitty browser in it with voice-chat that is obsolete compared to teamspeak/mumble/ventrilo/skype/whatever, that would be nice.
I don't hate Steam, but I don't really like it either. I like having a box, I like that "new game smell," I like having a manual, I like all of that kind of stuff. I mean, if a game is 5 dollars on Steam and 30 dollars retail, I'm buying it on Steam, but still...it's more of a necessary evil these days than anything else, but I much prefer it to, say, games for windows live or XBLA. I kinda like Origin though, since it's similar to Steam but actually allowed me to activate some old boxed game codes on there.
I know I'm in the minority but if I could just start up the game EXEs without Steam, I would. It adds no value to me. I don't need ads coming up when I start my game/end my game, I don't need "update news," I don't need to auto-patch a game that I didn't tell you to patch that I never play, tying up my internet connection, or god forbid I don't WANT you to patch it and I want to play it anyway, nope, everything must the latest version, even if it's a game where fan-made patches are better than dev-made patches. "verify integrity of game cache ohohoho"
Sorry, I'm gettin' carried away. My point is that I don't need a friends list, a browser, screenshots, videos, profile pages, achievements (don't get me started on them), recommendations, trailers, "summer camp" "potato hunts" and other such bullshit, I just want to play the fucking game.
Bottom line is I use it, I like it, I can put up with it, but god damn it can be annoying.