I found a very interesting article about player psychology in gaming, particularly regarding rewards and how to keep players hooked. Written by none other than the Lead Player Research at Bungie. Here is the link for anyone who is into this kind of stuff http://www.gamasutra.com/view/feature/131494/behavioral_game_design.php EDIT: If this gets enough attention, I might add a tl;dr resumed version for anyone interested Cheers, guardians *gets into the little wheel thingy that rats have in their cages*