Game designers can answer the question. http://www.theoryoffun.com/ http://www.theoryoffun.com/ http://www.gamasutra.com/view/feature/129948/the_chemistry_of_

Game designers can answer the question. http://www.theoryoffun.com/ http://www.theoryoffun.com/ http://www.gamasutra.com/view/feature/129948/the_chemistry_of_game_design.php http://www.gamasutra.com/view/feature/129948/the_chemistry_o... http://www.gamasutra.com/view/feature/131802/glory_and_shame_powerful_.php http://www.gamasutra.com/view/feature/131802/glory_and_shame... Off the top of my head.