Emotions that simmer beneath the threshold of awareness can have a powerful impact on how we perceive and react, even though we have no idea they are at work. Take someone who is annoyed by a rude encounter early in the day, and then is peevish for hours afterward, taking affront where none is intended and snapping at people for no real reason. He may well be oblivious to his continuing irritability and will be surprised if someone calls attention to it, though it stews just out of his awareness and dictates his curt replies. But once that reaction is brought into awareness — once it registers in the cortex — he can evaluate things anew, decide to shrug off the feelings left earlier in the day, and change his outlook and mood.

Daniel Goleman in Emotional Intelligence