The most import thing you'll ever know about humans: they are not actually rational. Most of the time they act under emotional and / or subjective prerrogative

The most import thing you'll ever know about humans: they are not actually rational. Most of the time they act under emotional and / or subjective prerrogatives - not actual facts nor rational cost/benefits prerrogatives- commiting themselves to apparently rational actions within the rationality established by the emotional / subjective prerrogatives. Sometimes, under certains circumstances - some predectible, some not - they act within rational constrains, but many of these are usually some cognitive bias in motion, not actual rational thought.