The events industry is growing every year, the number of events is increasing, and their role in society is becoming more significant. Satisfied participants are the key to successful events and the main objective of event organizers. The aim of the article is to understand what costumers consider more important when attending mega-events. A quantitative survey design was adopted by deploying the American customer satisfaction index (ACSI) that included an event specific customer value package in the context of the EXPO Milan 2015 mega-event. Results demonstrate that expectations of visitors, staff, and volunteers vary considerably, and so do the levels of satisfaction. They also highlight that, alongside other customers' priorities such as cleanliness and safety, capacity plays a role in determining satisfaction. This article presents the summarized findings of a broader study.