The three foci of rigid attitudes are one's own valued behaviour and characteristics, the valued behaviour and characteristics of other people or the valued aspects of life. Rational Emotive Behaviour Therapy (REBT) theory argues emotional well-being and psychological health can be achieved through the development of flexible attitudes towards one's valued behaviours and characteristics, the valued behaviours of others and the valued conditions of life for us and others. REBT theory, however, points out that it may not be easy, and is sometimes rather difficult, for humans to maintain a flexible stance in the face of adversity, particularly with important matters. From rigid attitudes which lie at the core of emotional disturbance come derivative or secondary attitudes which are extreme in their nature. In English flexible attitudes are expressed, initially, with words like wish, want, desire, hope and prefer and then a negation that these must be met.