The Omnipresent Wobbling Tables

Why do all tables at restaurants, invariably, wobble?

What goes on in those planning sessions when restaurant owners are picking the furniture.

Do they specifically instruct the manufacturers to make furniture that wobbles?

Do they intentionally finish the floor unevenly?

Why?

What is it?

Is it cheaper that way?

Do they hate their customers so much?

What is it?

And that trick that waiters do, their solution, to fold up a napkin and place it under the shorter leg, while we watch with renovated vigor and enthusiasm.

“He is going to fix it” we feel gratified.

What is this universal mystery?

Who is behind it?