Whenever we feel that we are definitely right, so much so that we refuse to open up to anything or anybody else, right there we are wrong. It becomes wrong view. When suffering arises, where does it arise from? The cause is wrong view, the fruit of that being suffering. If it was right view it wouldn't cause suffering.
But what if pleasure and pain should be so closely connected that he who wants the greatest possible amount of the one must also have the greatest possible amount of the other, that he who wants to experience the "heavenly high jubilation," must also be ready to be "sorrowful unto death"?
If to enjoy even an enjoyable present we must have the assurance of a happy future, we are “crying for the moon.” We have no such assurance. The best predictions are still matters of probability rather than certainty, and to the best of our knowledge every one of us is going to suffer and die. If, then, we cannot live happily without an assured future, we are certainly not adapted to living in a finite world where, despite the best plans, accidents will happen, and where death comes at the end.
I do not perceive even one other thing, O monks, that when undeveloped and uncultivated entails such great suffering as the mind. The mind when undeveloped and uncultivated entails great suffering.