Not having an agenda has long been considered one of the ultimate unforgivable sins in the land of endless meetings. This mythology obscures the reality that at the root of dysfunctional meetings are dysfunctional conversations.
Functional conversations without preset agendas are incredibly more productive than dysfunctional conversations with preset agendas. Agendas tend to create a two class system of people with and without the power to declare agendas, and as such prevents the kind of trust required for groups to make smarter and faster decisions.