Nearing a decision point, online traffic maps recommend a less-crowded route over the other ways with several slow spots. For most of us, the choice seems clear. Still, have you ever wondered whether this collectively preferring one path may result in a new traffic jam along the chosen road? Indeed, traffic congestions constantly change as the accumulation of drivers’ preferences for the “faster path” create new problems. These alternating groups in a system are called a network oscillation. From roadways to computer cable routers and blood vessels, our life is woven in networks of networks. Oscillation is an ubiquitous phenomenon of networks, which are characterized by sets of nodes and paths to choose.