Repression by far is my favorite defense mechanism. Though the one I usually practice is displacement, I recently discovered that you can wilfully raise your defense walls with Sigmund Freud's concepts. I always thought this happens automatically, but I was surprised I managed to send bittersweet memories down the royal road of the unconscious.
I learned from someone that if you don't talk about a thing or think about it, it might as well have not existed in the first place. I forgot the name of the concept but this idea is quite similar to an ancient chinese riddle: If a tree falls in a forest and no one is there to hear it, does it make a sound?
If I don't talk about what happened or think about it, maybe I can deceive myself into thinking that it never happened. Of course, distant echoes from another time still creep in my head, but I flush these thoughts away and focus my thoughts and my energy into something else. It actually works. I must admit, I still am sad, but I don't really know why. Eventually, through repression, I let go of all my angst, and emerged with what Alfred Adler would call a healthy personality. Now, I can think about things related to what recently happened without bursting into histrionic tears [I'm exaggerating to prove a point]. This I guess is the Freudian definition of moving on.
The Seven Habits of Highly Effective People author Stephen Covey states that unexpressed feelings never die. They are buried alive and come back later in uglier ways. But so what? I'd rather have it ugly and happy than pretty and sad.