“I include the natural human reactions to both kinds of loss experience—the loss of the possessed reward and the loss of the almost-possessed reward—under one description, Deprival-Superreaction Tendency.” “The quantity of man’s pleasure from a ten-dollar gain does not exactly match the quantity of his displeasure from a ten-dollar loss. That is, the loss seems to hurt much more than the gain seems to help. Moreover, if a man almost gets something he greatly wants and has it jerked away from him at the last moment, he will react much as if he had long owned the reward and had it jerked away.” “In displaying Deprival-Superreaction Tendency, man frequently incurs disadvantage by misframing his problems. He will often compare what is near instead of what really matters.” “A man ordinarily reacts with irrational intensity to even a small loss, or threatened loss, of property, love, friendship, dominated territory, opportunity, status, or any other valued thing.” “It is almost everywhere the case that extremes of ideology are maintained with great intensity and with great antipathy to non-believers, causing extremes of cognitive dysfunction. This happens, I believe, because two psychological tendencies are usually acting concurrently toward this same sad result: (1) Inconsistency-Avoidance Tendency, plus (2) Deprival-Superreaction Tendency.”

The tendency to seek information even when it cannot affect action. People tend to believe that the more information that can be acquired to make a decision, the better, even if that extra information is irrelevant for the decision.

Users have a propensity to best remember the first and last items in a series

“Sometimes you may want something to be true so badly that you fool yourself into thinking it is likely to be true. This feeling is known as optimistic probability bias, because you are too optimistic about the probability of success.”

Sixty percent of software’s dollar is spent on maintenance, and sixty percent of that maintenance is enhancement.

Premature optimization is the root of all evil.

The expected cost of a randomized algorithm on the worst-case input is no better than the expected cost for a worst-case probability distribution on the inputs of the deterministic algorithm that performs best against that distribution

“There is a broader class of unintended consequences to similarly watch out for, which also involve making seemingly good short-term decisions that can still add up to a bad outcome in the long term. The mental model often used to describe this class of unintended consequences is called the boiling frog: Suppose a frog jumps into a pot of cold water. Slowly the heat is turned up and up and up, eventually boiling the frog to death. It turns out real frogs generally jump out of the hot water in this situation, but the metaphorical boiling frog persists as a useful mental model describing how a gradual change can be hard to react to, or even perceive.”

“Extreme, consequential events (that end in things like financial ruin), but which have significantly higher probabilities than you might initially expect.”

The tendency to like things to stay relatively the same and be reluctant to any change. The current baseline (or status quo) is taken as a reference point, and any change from that baseline is perceived as a loss.

In many naturally occurring collections of numbers, the leading significant digit is likely to be small

“A frame-of-reference mental trap (or useful trick, depending on your perspective) is framing. Framing refers to the way you present a situation or explanation … Multiple framings can be valid yet convey vastly different perspectives.”

More probable behaviors will reinforce less probable behaviors

An exception to the fundamental attribution error, when people view others as having (situational) extrinsic motivations and (dispositional) intrinsic motivations for oneself

When people view self-generated preferences as instead being caused by insightful, effective and benevolent agents.

People judge an experience largely based on how they felt at its peak and at its end, rather than the total sum or average of every moment of the experience.

“The Pareto principle can help you find high-leverage activities. It states that in many situations, 80 percent of the results come from approximately 20 percent of the effort. Addressing this 20 percent is therefore a high-leverage activity.”

It is true complex systems may be expensive, but it must be remembered that they don't contribute much. Short version, it costs a lot to build bad products.

There's never enough time to do it right, but there's always enough time to do it over.

As an E-type system evolves, all associated with it, developers, sales personnel and users, for example, must maintain mastery of its content and behaviour to achieve satisfactory evolution. Excessive growth diminishes that mastery. Hence the average incremental growth remains invariant as the system evolves.