ACHIEVEMENT!
It's not a fuckin consipiracy. It's psychology, something that's called operant conditioning. It's a positive reward system that should keep people playing the game and keep them addicted, I.E. more money for them (yay for them). Ever wonder why your cat (hypothetically speaking if you don't have one), who chooses to go wherever it likes, always seems to go back to your house? *Achievement!* (of food) that it doesn't get anywhere else, that's why.