Preserve the special stories and memories of the past.
Moving forward without the benefit of the past is to be cut adrift from the mother ship. You’re not really moving forward, you’re drifting and that seldom ends well.

alone, lost, and directionless.
The very term moving forward implies moving from a point in time and space towards a new point in time and space. Those different points in your past (traditions, experiences, memories, values, heirlooms) are mile markers and information signs that gives you direction, inspiration, and continuity as you move into a better future.
There’s a negative component of this as well. Because of bad experiences in their past, some are not moving forward, they are fleeing. While fleeing is often the wisest thing one can do, you must not flee forever. There comes a time you have put enough distances between now and then and it’s time to turn a corner, leave the past, and start a new future.