Ipso Facto

People´s intrinsic actions are the best" publicity" to other people, if more than 2 people are staring at a laptop in a store, more people will arrive and stare at it, if someone yawns, other people tend to yawn too, if people think some train is about to leave the station, people will run for it, and if only one person does that, a bunch of new people are about to follow this"imaginary subway train"as well.