- Take an object
- Break it
- Put it back together (with any adhesive, that can do the job).
Try as much as possible, to make it look good as new. Good!
Now, take a look at that object. Does it look the way it used to? It might, but if you take a closer look, you'll find that you've left a scar. It might be very little, almost unnoticeable, but it's there, all the same.
People are the same way, when you hurt someone, they might forgive you, and let it go, but it doesn't really go, it just hides in the shadows of the mind, and will emerge when something happens to jog that memory. Think about this, the next time you want to hurt someone.
Scars may fade, but they last forever.