Why every body in univers and rain water drop is rounded shape ?

As you know that the every body in cosmic is in rounded shape like planets, satellites, stars and also rain water drop.

Because,
mass of the whole body creates a gravity. That is theoretically centered on the mass-center of the body itself.

And, the surface are is lesss in any rounded object as compare as square, traingle, cylindrical, etc.

Whan surface is less any abject than they are save large amount on energy.

And you know that every want to save their energy.