This is one of "22 virus definitions" (thought-mistakes that cause ineffectiveness and unnecessary negative emotions).
Jim’s boss is actually worried about his son. The look on the boss's face has nothing to do with Jim. So Jim is feeling bad unnecessarily because of his thought-mistake. And his bad feelings might interfere with his work. It certainly doesn't help him feel better or get more done. And to whatever degree it makes him feel worse or get less done, Jim’s conclusion is self-defeating.
Whether one of your conclusions is self-defeating or not is an entirely separate issue from whether your conclusion is true or not.
Some conclusions are verifiable. I have red hair. That’s a fact. You can verify it. But sometimes you don’t really know if a statement is true or false. For some statements, the question of true or false doesn’t even apply (for example, an overblown generalization such as, “society is evil” can’t be rationally argued one way or the other without being ridiculous). But if a negative thought is impairing your ability, it is counterproductive to keep thinking it, whether its truth or falsity can ever be determined.
For example, let’s say you’re lying in bed obsessing over the thought, “I’m an insomniac and will never again get a good night’s sleep.” The conclusion itself can keep you awake, so it is self-defeating to think it, whether it’s true or false. It's a self-fulfilling prophesy.
Many pessimistic thoughts are like that: They are self-fulfilling and therefore not useful thoughts. They aren’t true or false. But they make themselves true by thinking them.
A woman wrote to me and said her grandmother always used to say, “Hell is right here on earth.” That is an example of a demoralizing explanation of setbacks. But is the explanation accurate? Is it true? You can’t really say.
So the question then becomes: Is the thought useful? Clearly that grandmother’s conclusion about life, the assumption she made that "hell is right here on earth," produces a feeling of sadness, demoralization, hopelessness, and it would not help her overcome the challenges in her life. Not only that, but those feelings are unhealthy. And in fact, the grandmother was constantly grumpy and depressed.
With many of your conclusions, you can destroy them by simply realizing they are untrue. But if you can’t determine the truth of a negative conclusion, then look to see whether it is self-defeating. If you don’t know if it's true, but you know it is self-defeating, then your belief in it will diminish as soon as you realize that fact.
See the complete list of definitions: The 22 Virus Definitions.