Why this is a mistake: Flashbacks and memories are not wrong in and of themselves, but they are often used wrongly. Time, for most of us, is linear and moves forward. In the same manner, time in a story or article is linear and moves forward—because that’s what people naturally understand and expect. When you use a flashback or a memory, then, you are going against the natural flow of things.
(Many writers don’t understand the difference between a flashback and a memory. If you’ve ever been divorced, you will understand the difference. A flashback is a portrayal of what actually happened. A memory is what someone remembers happening. A memory is tainted by everything that happened after the event and by a person’s emotions.)
Many writers fail to make it very clear to the reader when they have entered a flashback or a memory. I once read a manuscript in which the author had put the story into a flashback inside of a memory, inside of another memory, inside of flashback. That’s not good.
The solution: Make sure you have a very good reason for using flashbacks or memories—they must be essential to understanding the present story.
Also make sure you know whether you need a flashback or a memory, as each will be written differently and interpreted by the reader differently. A flashback requires a verb-tense transition, whereas a memory requires an action transition. Using clear transitions will ensure that readers
know when they are entering and leaving a flashback or memory.