Final answer:
Self-defining memories are not always positive experiences.
Step-by-step explanation:
The characteristic of self-defining memories that is NOT true is that they are always positive experiences. While self-defining memories are emotionally intense and contribute to our sense of self, they can be both positive and negative experiences. For example, a self-defining memory could be a negative experience, such as a failure or a traumatic event, that has shaped who you are.