Perception is Everything

A few life lessons:

(i) Perception is Everything. A lot of times, what you do isn't as important as how people perceive it - the thought processes and the effort behind the action
(ii) People are Inherently Selfish, and Self-serving. I needn't explain this, really.
(iii) Logic is always tainted by Emotion. No matter how logical a person seems to be, invariable emotion comes into play. Then again, without emotion, we probably wouldn't make extremely logical, rational choices (re: some psychology stuff). Example, because of pain, we seek to rationalise our future choices. If we understand that the pain is only temporary or would not affect our long/medium-term choices or opportunities, we don't change, simply because change may entail a greater amount of effort that cannot be logically justified.
(iv) You will be Screwed. People's needs and wants will always be in contention with other's needs and wants. In the short-run, perhaps cooperation may lead to better outcomes for all. But in the long-run, it's a zero-sum game.
(v) No Matter How Much You Think Ahead, You'll Always Miss Something. And that one thing will ALWAYS be the most troublesome, niggling matter.