In the world of dreams the rules of reality do not necessarily apply. Each dream is unique and it's a direct link to the soul and spirit. Psychology provides its own theories on what dreams mean, but so did tradition and the study of dreams for thousands of years before any relevant science had developed.
Dream Meanings - Excursion
If you go on an excursion with a group, then you will have some unexpected joy. If you go on an excursion to a mountain and have food with you, then you will have some distress.