The author connects the beginnings and development of emotions to the needs of an individual. The classification of emotions is offered depending on precise mirror symmetry: anger - shame, sorrow - joy, fear - fearlessness. Emotions' alteration corresponds to "emotional wave" model: at first negative emotions are displayed in turn - fear, sorrow, anger,- and then positive ones - shame, joy, fearlessness, always in the same fixed strict sequence. Each emotion's development has wavy form too; the latter is illustrated by the matrix worked out by the author.