Indeed, this fact of life — that there is often a gap between the way in which we perceive phenomena and the reality of a given situation — is the source of much unhappiness. This is especially true when, as in the example here, we make judgments on the basis of a partial understanding, which turns out not to be fully justified.
From “Ethics for the new millennium” by His Holiness the Dalai Lama – © 1999, The Berkley Publishing Group