The differences are manifold. Start with the purpose - modern government exists to serve all of society, which it mostly does. The mafia exists to serve the mafia, although it can be incidentally generous with the public. The social contract between the public and the government is that revenue the government takes in through taxes is spent on things that help the public - schools, roads, emergency services, etc. The public has substantial if indirect influence on this balance, via elections. Of course, some people won't be happy with the arrangement, but the majority are generally satisfied.
Additionally, modern government functions in part by a monopoly on the use of violence, which we agree to as part of the social contract. Individuals who refuse to participate in the social contract are subject to government violence, whether they're not paying their taxes, or shooting their neighbors. As part of the contract, the government is not to abuse that monopoly on violence at a large enough scale that most of the public feels threatened by government itself.
The differences are manifold. Start with the purpose - modern government exists to serve all of society, which it mostly does. The mafia exists to serve the mafia, although it can be incidentally generous with the public. The social contract between the public and the government is that revenue the government takes in through taxes is spent on things that help the public - schools, roads, emergency services, etc. The public has substantial if indirect influence on this balance, via elections. Of course, some people won't be happy with the arrangement, but the majority are generally satisfied.
Additionally, modern government functions in part by a monopoly on the use of violence, which we agree to as part of the social contract. Individuals who refuse to participate in the social contract are subject to government violence, whether they're not paying their taxes, or shooting their neighbors. As part of the contract, the government is not to abuse that monopoly on violence at a large enough scale that most of the public feels threatened by government itself.
Et cetera.