I'd like to talk about good and bad marketing/advertising. Have you ever seen those cinematic trailers for games that are completely different from how the game actually is? It may initially draw in a bigger crowd, but result in less customers. It draws in the ones, who would be interested even without the "non-existent" features, and those, who otherwise wouldn't be interested without those "non-existent" features. When they figure out those features don't exist, obviously, the latter ones would leave. However, it is likely to cause the ones that would be interested without the "non-existent" features as well to leave, if it catches their interest. Because people can only consciously focus on one thing, and if the "non-existent" feature catches the person's interest, then that will be focusing on what they're interested in the most. It's like having a person interested in object A and then telling them about this amazingly cool object B and then letting them know that B doesn't exist. Now, A isn't as interesting or appealing to the person as it used to be, because they've been exposed to B, which was apparently more appealing to them. (I think it can be compared to eating something really sweet and good tasting, then try something less sweet). So now, being less interested in what they were originally interested in, they are less inclined to think about it now and all the while they've blocked off thinking about the "non-existent" features, because the context* has changed, because it doesn't exists. This is the effect of bad marketing.
How about good marketing? I'll give an example for this. In those same cinematic trailers, the fighting is always alot more astonishing and intense, isn't it? Well, in this case, most of the time it's okay. In fact, it's beneficial, because it raises the audience's imagination. While in the game, the characters may just hit in auto-attack, but with that advertising, some players may imagine their characters doing all those cool moves and see the auto-attack as only a simulation of what's going on. Therefore, they enjoy the game more due to their additional imagination and thinking. But, really why is it okay to mislead here? Well, the reason is that combat is the most learned about thing before entering a game. Combat is usually the main focus of any game. Therefore, in in-game trailers, on websites, in screenshots, etc. the players already know exactly what the combat is truly like from the vast amount of sources available about that. Therefore, the context* is unlikely to change once the person plays the game and the player doesn't get disoriented unlike in the above paragraph...
The difference between good and bad advertising can be viewed as this: bad marketing results in the separation of reality and imagination, and blocking of imagination; good marketing results in the combination of reality and imagination, thus allowing more variation of thoughts.
context* = player's understanding of the game world or environment/surroundings