I was listening to an audio recording of Earl Nightingale and heard him say something profound. Actually, Earl said a lot of profound things, but one led to me writing this.

Successful people stay on top of things. Unsuccessful people have things stay on top of them. 

When circumstances keep forcing your hand, causing you to be constantly reacting to life and defending yourself to the world, things are on top of you.

This happened, so I had to do this. Then this changed, so I had to go here. Then she did this, so now I'm in this situation.

That's defense.

Staying on top of things means you dictate the terms of engagement more times than not. Your energy and attitude determine how things will go, often before they even happen. And even when things don't go according to plan, your mentality tunes things in your favor anyway.

This happened, so I did this. Now this is the situation. He said this, so I responded this way. I'm doing this now, and no matter what, I'll get either of these outcomes.

That's offense.

I used to watch a TV show featuring Cesar Milan, a well-known dog specialist. In one of his books, Cesar explained that dogs, being pack animals, always seek a leader when traveling. So when you take a dog on a walk, either the human will lead the dog or the dog will lead the human (take note the next time you see a dog being walked as to who's running the show).

Life is the same way. It will control you and force you to bend to its will, or you will take the wheel and control the outcome. There is no in-between.