GTA V's strange, cross-generational release schedule meant that the PC version only came out in 2015, which is all the excuse required to include this absurdly entertaining clip in the list. Buses, by their very function, attract all kinds of interesting people, so while one guy responds to a tailing police car by stepping off the bus and shooting at the officers, a good civilian gets gets off right behind him and shoots him in the back of the head, which leads to another passenger stepping off to shoot that person, and so on until we have a glorious domino-effect of shootings where you lose all track of who's doing what and why. A beautiful, ultra-violent example of emergent gameplay.