Static electricity is caused by creating friction along with the sudden separation of two dissimilar materials.
Friction causes heat which in turn excites the molecular particles.
When separation occurs, one material becomes more positive while the other becomes more negative. ESD is when the static electricity moves toward a ground. You feel ESD at 3,000 volts but it only takes 30 volts to damage an electronic component. When you have been charged with static electricity and touch a sensitive computer component, you discharge that electricity into the component. The electricity follows the wiring and when the charge nears a metal part with an opposing charge the internal wires and elements of the component may explode or weld together.