Why does my neck always crack when i roll it to the left but not when i roll it to the right?

Very non-specific: Like cracking your knuckles, exact mechanism causing the "cracking" sound produced by bending/compressing/rotating joints is unknown. Few causes have been suggested including stretching of ligaments; small pockets vacuum cavities forming within synovial fluid contained in joints which with certain motion pushes the cavity to one corner, leading to rapid collapse of cavity, producing a sharp sound.