Look at lightning. It's not a circuit, there is no closed loop. Yet, it discharges to other clouds and to ground.

Actually there is, it has been found as charged thunder clouds travel, there is an equal and opposite charge traveling across the ground under it, until a point is reached where the charge can travel from cloud to ground.
Max.

 

A couple of other things:

We would like are metalic appliances, our sink, our bathtub to be earthed so that everything is at the same potential.

With the event of computers and appliances that depend on ground for communication, we should have two grounds, one being earth and one being a reference.

Daisy-chained outlets are bad because a fault raises the ground potential downstream (toward the panel).

There are orange colored outlets in the US that have an isolated ground.

Certain types of buildings like hospitals and radio transmitters may actually have both grounds. Protective and a reference.

Storms can really mess up ground potentials and therefore special grounding techniques are used to ground the sidewalk around a pool.

In a computing facility where I used to work there was a storm and it took out stuff on the opposite wall because of the difference in the ground potential. It was replaced with fiber communication.

In the US, the ground is supposed to only carry fault currents, but it is also a reference for telephone, cable and power. Technically, the reference for the house should be at one point.

Sub-panels for non-detached spaces are referenced to the main panel.

 

We would like are metalic appliances, our sink, our bathtub to be earthed so that everything is at the same potential.

With the event of computers and appliances that depend on ground for communication, we should have two grounds, one being earth and one being a reference.
.

Along time ago in the UK when the sink/bathtub hot-cold-waste where all metallic, there was a regulation that all three had to be bonded under the each sink.
As to PC's., for desk tops and tower types, the PS common is bonded to earth ground through the MOBO mounting.
Max.