Human memory is actually incredibly selective, and we often have no control over what we remember and how. Probably, each of you have had several cases when some completely unnecessary and petty nonsense crashed into your memory, but something really important left your mind almost immediately.
And this happens more than once or twice in life - even half a century later, we remember who made that silly fumble in a meaningless regular season football game, but at the same time, we can forget the date of our own wedding anniversary (God forbid doing this, in fact, it’s better to write down it somewhere, just believe me!) It's just how our memory works, and there's nothing to be done about it.