Irvin Yalom (Existential Therapy Expert) 11 Reasons Groups Work So Well Altruism 2. Universality: you’re not the only one 3. Installation of hope 4. Catharsis 5. Group cohesiveness 6. Imitative behavior 7. Family reenactment 8. Imparting Information 9. Interpersonal Learning 10. Socialization Techniques 11. Existential Factors: discover life can have meaning even when it seems unfair and unjust at times.