One thing which really grinds my gears is when a computer game cover completely obscures the type of the game. Most importantly, many games completely obscure and/or fail completely to mention whether the game is mainly single-player or multiplayer based.
Most online multiplayer games have a single-player mode which can be played offline. However, in most cases this is not really a game at all. It's more like a training tutorial for the actual online multiplayer mode. In a few cases the offline single-player mode might somewhat emulate the multiplayer mode by using computer-controlled players, but effectively it's just the same multiplayer game but without the other (real) players.
Many of these games completely obscure this fact in their cover descriptions. Often they will use expressions which give the impression that the game has a multiplayer mode as an additional option, while making more or less obscure references to a single-player mode, but never making it clear whether the game is a multiplayer-based game, or whether it really has a real single-player mode (which is not just an emulation of the multiplayer mode with computer-controlled players).
Personally I find online multiplayer games quite boring, and thus I'm not very fond of them.
What makes this whole thing confusing is that not all games with an online multiplayer option are multiplayer in nature. For example most first-person shooters, such as for example Half-Life 2, are definitely single-player games with an optional multiplayer mode as an added bonus. However, the multiplayer mode is not the core playing mode of the game, just a side feature.
But then there are games which are basically exclusively intended for multiplayer play, where it's the offline single-player mode which is an additional (and often quite poor) additional bonus, as described above. Most "arena"-type and "counter-strike"-type games are like this.
Some time ago I was at a game shop, browsing for some cheap games. Some of the cheap games had a "buy 3, pay 2" offer, and I had already chosen 2 games and was looking for a third one to get for free. I wasn't seeing anything really interesting, and the only thing which looked like it could perhaps have potential was a game named Lord of the Rings Conquest.
That's a perfect example of a game which completely obscures its nature in its cover descriptions. It mentions a 16-player online game mode, but in such vague terms that it leaves it completely unclear whether that's actually the main playing mode, or just an added bonus. I even asked the salesperson whether it was a multiplayer or single-player game, and he didn't have any idea. Another salesperson said that it does have a single-player mode (but also in rather vague terms).
Well, the game resulted to be basically Team Fortress 2 in a LotR setting. The single-player mode is more or less the online mode with computer-controlled players, and quite boring. It has no story to speak of, and the gameplay is quite repetitive and boring.
A similar situation happened to me with Left 4 Dead. Again, the descriptions of the game are so vague that they don't make it at all clear whether it's an online multiplayer game with an offline emulation mode of the online play, or whether it really has a real single-player story mode. I bought it like an idiot, only to discover that it has no real single-player mode. The offline mode (with computer-controlled players) is quite boring.
Games not making their nature unambiguously clear is a rip-off in my opinion. Not all players enjoy arena-style online games, and they don't want to waste their money on them. Making a game cover ambiguously look like it does have a real single-player story mode (rather than just an emulation of the online multiplayer mode) is like a fraud. It really pisses me off.