You can't remember every detail of something that happened, so what you do remember is what happened. I don't know, I can't really explain it without sounding stupid..
The memory it's not perfect. In fact, all we have is little clues about something. The more important to you (for whatever reason) it is the "thing", the more clues you remember. So, when you remember something, you'll never remember it as it was. You will remember things that are in fact true, but the rest of it it will be invented, based on how you felt back then, how many "clues" you've got, and more complicated process.
That's why diferent people have diferent memories about the same story.
And to finish what darkanhell said, and what fragments of what actually happened that you remember, becomes what happened because that's all you remember.
And this is one of my screensavers :)
That's why diferent people have diferent memories about the same story.
And this is one of my screensavers :)