One thing to note about the  past -

What's done is done, the die is cast,

And we are bound to move away,

Obliged to face each passing day. 

Nothing can be changed but then

the bad stuff shouldn't happen again.

If we insist on judging what went before

Let's do our own best to make sure

We learn from what the past can teach

With its "don't do" lessons within reach

....................................................................