Bandwagon Effect: A psychological phenomenon whereby people do something primarily because other  people are doing it, regardless of their own beliefs, which they may ignore or  override.

Godwin’s Law –  As an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches 1

Hanlon’s Razor – Never attribute to malice that which is adequately explained by stupidity.

Murphy’s law – Anything that can go wrong will go wrong

Osborne Effect – The detrimental impact upon the sales of the current product as a consequence of announcement of a future product ahead of its availability.

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

Peter’s Principle – In a hierarchy every employee tends to rise to his level of incompetence

Doing a Ratner – Destruction of market value by denigrating the quality one’s own product

Stigler’s law of eponymy – No scientific discovery is named after its original discoverer

Zeigarnik effect – People remember uncompleted or interrupted tasks better than completed tasks

The Four Agreements – Don Miguel Ruiz’s Code for Life
Agreement 1 Be impeccable with your word
Agreement 2 Don’t take anything personally
Agreement 3 Don’t make assumptions
Agreement 4 Always do your best