It's funny how we, humans, manage to degenerate powerful natural instincts into regressive psychological traits. Look at that little coyote pup. Something has attracted his attention. He is in full alert, assessing the situation, deciding if its dangerous; ready to fight or flight – a perfect display of a healthy defense mechanism crucial for survival.
People are granted the same insitincts. Of course, those of us living in "civilized" conditions are rarely presented with real danger. On the other hand, mentally we are constantly put to test. The instincts are pushed into psyche, and there, they deteriorate into Freudian ego defense mechanisms, which can get neurotic and pathological.
CFOs and Controllers deal with defensiveness and rationalization (aka making excuses) all the time. People become defensive at the slightest hint of criticsm, which frequently exists only in their imagination. They don't understand that instead of helping them to survive, this degenerated mechanism makes them more vulnerable by exposing their insecuruty, fearfulness and anxiety.
A few years back I had an employee who was the best expert of trade finance documentation I've ever met. At the same time, he was an incredibly difficult person. Eventually I found out that this guy had a misfortune of being raised by an extremely critical adoptive father. As unlikely as it sounds, in the early 80s, just 20 years old, he got hitched to a woman who hated everything about him. As the result, he developed a severe case of defensiveness.
Just invinting him to my office to discuss a business issue was enough to put him into a state. Walking into my door, he already looked like an angry animal forced into a corner and ready to bite. It would usually take me at least ten minutes of casual small talk to bring him back into normality, before I could address the matter at hand.
Of course, on few occasions I needed to point out a mistake or an inaccuracy. What a nightmare! He wouldn't let you finish the first sentence: "I am swamped! You gave me too much work! It is impossible to deal with that bank! I will not let you blame me for this! " he would shriek, even though it was never about the blame. His desire to shield himself from the imaginary threat was so strong – like a child, he would cover his eyes with his hand, avoiding your eyes. He looked helpless, pitiful, and guilty. Most importantly, the problems remained unresolved. It was really painful.
Here is my advice: don't get defensive when you are criticised, justly or unjustly. Listen. Think. Evaluate. Maybe you will hear some constructive insights. Maybe you could have done something differently and achieve better results. Recognizing that will give you an opportunity to (1) disarm your opponent by owning up to your mistake and (2) find ways to avoid this situation in the future. At the very least, you will save yourself from an emotional sparring match that cannot resolve anything. Trust me. I've been there – on both sides.