Why Can't The Past Stay In The Past?

According to Wikipedia, 'the past is a portion of time that has already occurred; it is the opposite of the future; it is regarded as the conglomerate of events that happened in a certain point in time'.

As hard as I try to keep the past in the past, it always seems like the past wants to find a way to come to the present. Certainly my present is much better than my past. Could it be better because the past is not a part of my present? Honestly, I can see why the past would like to become a part of my world.

But, if the past stopped to think about why it is in the past, wouldn't it realize that it was never meant to be in my future? Hence the reason it is in the past where it rightfully belongs.