Why would you get an electric shock if you touched a wire?

Live wires are dangerous because they carry current to the appliance they're connected to, at very high voltages. This means the wire has a high potential voltage, whereas a human has zero potential voltage and so there's a big potential difference between them. This causes the current to pass through the body, hence the feeling of an 'electric shock'. So in summary:live wires have a high potential humans have zero potential the high potential difference means the current passes through the body