Electricity always seeks every available path to ground through conductors. Good conductors are:
Your body is 70% water and is a dangerously good conductor of current. So, if you're grounded and touching an energized bare wire, electricity will pass through you to the ground. An amount of electricity as small as that found in a typical Christmas tree bulb can be fatal. Or, the shock can easily cause serious falls, burns, cuts or internal bleeding.
Damaging a line is not only dangerous, it also will be expensive if you have not contacted Diggers Hotline ahead of time. Call 811 before you dig.