The GDR had possibly the highest ratio of secret police (Stasi) employees per # population in world history, it was really ridiculous how paranoid that government was. About 0.5% of the population were Stasi employees and an additional 1% were "inofficial employees", informers.
Its also the measly rewards that they did it for. In a dysfunctional economy, some people sold out there family and friends, cutting them of forever, for as little as a cheeseburger now and then.
