There is also Ulmann's Razor (Mitchell Ulmann): When stupidity is a sufficient explanation, there is no need to have recourse to any other. Hanlon's is a variant of this.
Also, Schiller's Amendment (Friedrich von Schiller): With stupidity the gods themselves struggle in vain.
An entertaining book is available to explain all these laws, Unwritten Laws, The Unofficial Rules of Life, by Hugh Rawson.
* * * Since we are destined to live out our lives in the prison of our minds, our one duty is to furnish it well~Peter Ustinov
