The famous literary example, of course, is Proust and the madeleine. Consider a child who is nonviolently and noncoercively sexually fondled by a trusted adult. The child might not even interpret what is happening as wrong at the time, and may come to view the incident as abusive only later in life when the child acquires his or her sexual morality. Memories of traumatic events are sometimes not stored in long-term memory. None of us has more than a handful of memories from the first six or seven years of our lives.
Emotional trauma does impair memory storage.
All interpretations are by necessity speculative. Schacter, for example, credits as a corroborated instance of recovered memory the case of R.C., a college professor in therapy. R.C. had a dream about a certain camp counselor, followed by recovering the memory of having been molested by the counselor. I do not consider this incident evidence of massive repression. For one thing, according to Schacter, R.C.'s experience with the counselor was not traumatic.