The story could be different than the one you have in your head. How you construe some experiences, have or will in the future radically change. But, all the time you think of the past as something fixed. 

You need to realize, the reason you remember the past is not to make an objectively accurate data unit of it, it’s so that you can use that information from the past to prepare you for the future, and our minds will not leave us alone until that has happened. If something negative has happened to you and you don’t know why and you don’t know what to do if that happens to you in the future, it will stay with you and this increases your overall physiological load. 

Your brain tells you how anxious you should be in a particular situation and it does this by keeping track of your past success and failure ratio in a given circumstance.