Happiness and Misery: Products of the mind.
“The great source of both the misery and disorders of human life, seems to arise from over-rating the difference between one permanent situation and another. Avarice over-rates the difference between poverty and riches: ambition, that between a private and a public station: vain-glory, that between obscurity and extensive reputation. The person under the influence of any of those extravagant passions, is not only miserable in his actual situation, but is often disposed to disturb the peace of society, in order to arrive at that which he so foolishly admires. The slightest observation, however, might satisfy him, that, in all the ordinary situations of human life, a well-disposed mind may be equally calm, equally cheerful, and equally contented. Some of those situations may, no doubt, deserve to be preferred to others: but none of them can deserve to be pursued with that passionate ardour which drives us to violate the rules either of prudence or of justice; or to corrupt the future tranquillity of our minds, either by shame from the remembrance of our own folly, or by remorse from the horror of our own injustice.” ~Adam Smith, The Theory of Moral Sentiments
My understanding of both the lecture and this quote is that we create our own misery when we contemplate, or dwell on what we could have or should have done. We remove ourselves from the present situation and into a state of melancholy.
We assume things would have worked out better had one thing gone differently. We have elaborate fantasy of what life would be like had something not occurred. This is nothing more than a waste of our precious time. To reflect on the past gives us valuable insight into how to behave in future. When this reflection becomes delusion, we are sucked into a world where everything isn’t quite good enough. This world of greed blinds us to the blessings surrounding us. We see the downside to everything, rather than the glass half full. Either way the glass has that same volume of water, only our outlook and disposition changes. Happiness is created and destroyed internally.
It is hard not to live in this manner and I struggle with it every day. Turn to others for support, find ways to keep yourself motivated and passionate about what can and will be, be open to the new possibilities of tomorrow and not stuck on the mistakes and misfortunes of yesterday.