It appears that the key to happiness might be unlocked if only we could understand our moods. So we constantly look for the cause of our happiness or the cause of our unhappiness, but sometimes this gets us into trouble.

Our moods are internal—more so than our sensations, which seem to be situated where our egos come in contact with objective reality. Our sensations are where inner and outer worlds meet. Our moods, on the other hand are wholly inside us, and therefore, we feel, must be completely transparent.

But there are at least two reasons for failing to see the cause of a mood; let’s say we're talking about unhappiness. Reason one is that the cause is not in the objective world, rather it is physiological (maybe the side effect of a drug) and therefore invisible. The other reason we may look in the wrong place is because the true cause is too painful. For example, let’s say that you are not succeeding in your career to the extent that you had imagined when you were younger. To admit that failure, even to yourself, might be too painful, so you look for another cause, and end up blaming your spouse. Or, not realizing that the drug you are taking is depressing you, you do a lot of soul searching for aspects of your past that could be making you sad; and you end up concluding that it is your failure to have a brilliant career that is bringing you down. Yet it isn’t; it’s the drug. On the other hand, you might think that everything in your life is fine (not admitting that it’s your marriage or your career that’s bringing you down) so you assume the problem is physiological, and you start taking vitamin E, or maybe you get a haircut or change your brand of orange juice.