I’d imagine gamers have honed their ability to look for things down to the point it can be considered some kind of art form. You can thank game developers for that. You’ve probably been ordered to go on so many collection runs or told so many times to keep an eye out for random items, hoarding and keen observational skills have become second nature.
Not everyone can push through the stresses of battle while at the same time being worried about whether there was a nice playing card laying around somewhere that they forgot to pick up. Also, few people would be willing to pursue that ongoing side-quest about killing X number of zombies to collect their turds or whatever it is. Several of you probably adopted the habit of keeping every single mundane object you come across simply because sometime later in the game, there might be an NPC that’s crazy enough to want them. It’s a staple of RPG’s, most of the time. Usually, the developers would justify your inane hunting and hoarding of useless crap with some kind of story: The NPC needs to assemble a necklace made of 20 wolves’ teeth, the NPC wants to study flowers, so your tough manly character is forced to gather them like a little girl…things like that.
RPG’s are famous for such quests, but other genres have them, too. FPS’s might shuffle you from encounter to encounter and from map to map, but hidden in several locations are items that may or may not have any relation to the game but need to be picked up by you, regardless. Maybe if I saw a laptop sitting on a table in the enemy stronghold I just bombed, I’d pick it up (CoD 4). If I saw Nazi gold laying around, I’d pick that up, too (Wolfenstein). If I saw a pigeon minding its own business, I’d make it so that it would be unable to do anything more complex than being dead (GTA IV). Aside from Shooters, there are also many Platformer adventure games that scatter hundreds or even thousands of a certain object in the game world for you to collect, like gems (Spyro the Dragon) or fruit (Crash Bandicoot).
Not many games these days are straight-forward and simply ask you to focus on one goal. Developers put in these scavenger hunts and collection quests so that the player will have something else to be occupied with, probably to keep them from getting bored, probably because it’s a cheap way to lengthen gameplay time and increase replayability value. Of course, aside from feeling good about yourself when you’ve finally gathered all that needed to be gathered, you are also given some kind of reward for your obsessive efforts: like cheat codes or a new cinematic sequence or whatever.
Don’t count on seeing this cliché disappearing anytime soon (or ever). It will persist, so keep your eye sharp and your pockets free.
There's a good reason for this, I swear.