Irrationality in Marketing

If we assume that human beings are all rational, almost to the point of robots with squishy parts, we can shrug off a lot of what goes on in business because we still believe that at the end we will make rational decisions and not be swayed by factors that don't have to do with the actual purchase of, say, a game, or its review. It seems clear to me, though, that there's more at work in our brains than just "rational processes."  Sometimes we'll go out of our way to avenge ourselves when someone is a jerk to us on the forums (or in person), we'll be appreciative when someone gives us a gift even though we know they want something from us, we'll automatically assume we're right and someone else is wrong a lot more than would seem statistically warranted...
 
These things are not completely under our supposed rational control; saying this, I know, is tantamount to heresy to many people, but they might admit, in private at least, that while they are completely rational, not everyone else is when it comes to certain weaknesses. The best we can do is guard against these sorts of influences, or at least be aware of them and artificially change our mind , but sometimes even that isn't enough.
 
Whether or not we have our shields up when going into the center of influence, say the Gamescom convention (a huge game faire being held in Germany), there's a part of us that knows we might get loot. Even if it's stuff we'd later consider to be worthless, like a badly printed mousepad, when we first get it I think it taps into the same region of our brain that tingles when we play games like Torchlight or Diablo. We like shiny things.
 
Market folks believe this, and know that if they can get you to associate that phatlewt feeling with picking up a shiny bauble with their company's name on it, that might tip the scales. AAA game companies have the kind of money that allows for that sort of influence, and so even though most of us won't even be able to fly to all these conventions throughout the year, we'll still get a trickle-down effect in the form of enthusiasm. Big-budget games become more than just software; they wind up being community events. Even when we say naysay in a discussion about one of these upcoming games, we're participating, keeping things active.
 
This all sorta rushed through my head when watching BlueXephos's Channel on youtube, where they usually run through adventure packs in good old Minecraft. They're covering Gamescom, and they're being a bit more honest about their hunger for freebies than many are. While it's hard to guess just how much the loot affects what people talk about, I imagine marketers wouldn't spend so much time and money crafting these things if they didn't have some sort of aggregate influence.
 
Yet, I want to close with another thought that sort of hooks on to this one like a Lego piece. Often economics, because of the difficulty of understanding the ever-changing marketplace, takes on aspects of a cult. There's a possibility that all the energy the marketers are spending on these baubles is actually wasted, that gamers and media members merely feel like they're getting away with something, even if what they're getting may not be all that great, and that what's really going on is that people who are marketing these shinies are fooling themselves into thinking they'll make a difference, merely because they see their peers doing it. They have the competitive drive to fight for everyone's attention using the same tactics their peers are, heedless as to whether or not it's actually worth it. That is, one might say, an irrational motive.