Often a person would rather be with his opposite than with one who is nearer his own level. When two who are of nearly equal strength meet they are not harmonious to each other. Students of breath will readily understand this; they know that there is a more active breath and a less active breath, and when both become of equal activity there is a sort of fight. If one person is a great singer and another is teaching voice-production they can agree together. There is no competition between them; the one wants to show himself, to show his voice, the other does not. But if there are two great opera-singers, a tenor and a bass, they will never agree; there is rivalry between them, they both want to be something.