Thinking Long-term is the only way to think...
But...
it can be disastrous in all other ways.
Take Enron, the corporate leaders fudged the books...made everything look good for a time. A short time. The results on its effects on the larger corporation and all its employees is sad on the grandest scale. Retirement fund gone. Employment gone.
On the micro scale, you consider cheating on an exam. You need this course to graduate. So you succumb to glancing on your neighbours test...it only took seconds and you have lost in the long term for a short term gain. But no one will find out...you missed the point. YOU KNOW and that is the most important person in this story. You steal a mark or two from a neighbour...you steal from your own conscience.
Guard that conscience. It is the only one you have...it is of great value. When our conscience is pure. We have confidence that others can only dream of. Every short term decision is likely the wrong decision... any doubt...just ask Adam and Eve.