It happens in a game called Rust. You start off in a random location looking for your friends and a place to set up some sort of base. As you go wandering around, some dude who’s been playing the game for a while comes up and just shoots you. Not because you posed a threat, you only have a rock. Or for your loot, you have none. No this is killing for the sake of killing. Barbaric. Then you finally find your friends after dying about 20 more times and life is just peachy. You have a hut, a gun and some actual clothing. You log off and the next day your camp has been blown up, raided and you are dead.
Commence a few more hours of you and your friends trying to find each other and shelter. You’ll end up under a rock cooking food and hoping that the night will go uneventful. At dusk, another friend finds you and waves a torch to get you to come his way. You go but so does everyone in the vicinity. Again, they don’t want your gear, they just want your head. One by one your friends disappear into the night or have been killed and you are desperately trying to smash someone else with a rock while they do the same and ultimately win.
Take three starts with some unclear directions and wandering about yet again to find your friends who have miraculously set up an actual building. Eventually you do find them and suddenly the game isn’t so bad. You have food, resources, a safe place to sleep and friends around you. But then you hear others outside. They taunt you, insult you, ask for resources or just ask that you be nice. You have seen too much though. You know they just want your metal regardless of what they say. Being nice and reasonable doesn’t get you anywhere with them. So you become them. You lure them into your lobby and gun them down. You sneak up on them and take them out. You kill just for the sake of killing and the circle of Rust is complete.