People often get weird and nasty online. This bizarre phenomenon surprised everyone in the earliest days of networking, and it has had a profound effect on our world. Nastiness also turned out to be like crude oil for the social media companies and other behaviour manipulation empires that quickly came to dominate the internet, because it fuelled negative behavioural feedback. Why does the nastiness happen? In brief: ordinary people are brought together in a setting in which the main – or often the only – reward that’s available is attention. With nothing else to seek but attention, people tend to become assholes, because the biggest ones get the most attention. This inherent bias toward assholedom flavours the action of all the other parts of the Bummer machine.