Why To-Do Lists Run Into Trouble

Hofstadter’s Law: It always takes longer than you expect, even when you take Hofstadter’s Law into account.

Murphy’s Law: If anything can go wrong, it will.

Finagle’s Law (a refinement of Murphy’s Law): Anything that can go wrong, will—at the worst possible moment.

Hanlon’s Razor (a corollary to Finagle’s Law): Never attribute to malice that which can be adequately explained by stupidity.

Callahan’s Principle (a corollary to Hanlon’s Razor): You can’t argue with stupid. [But just think how much time people waste trying.]

Brooks’s Law: Adding manpower to a late software project [and many other types of late projects] makes it later.

Optimism Bias: The demonstrated systematic tendency for people to be over-optimistic about the outcome of planned actions.

Parkinson’s Law: Work expands so as to fill the time available for its completion. And…

Parkinson’s Law of Triviality: Organizations give disproportionate weight to trivial issues.

Pareto Principle: Approximately 20% of your efforts will produce 80% of your beneficial output.

Sturgeon’s Law (an extension of the Pareto Principle): Ninety percent of everything is crap.

Law of Unintended Consequences: Any purposeful action will produce some unintended consequences.

David Allen’s Law: Surprise. Much of your work on any given day arrives unanticipated and unplanned.