I've been involved in a lot of meetings as of late, and one of the things I've realized, though I imagine I've already known this subconsciously, is that a meeting without an agenda is really like a car without a steering wheel. In both cases, the direction is uncertain, and it is unlikely that you'll be getting to where you hope to go.
I've organized meetings where I've created agendas, and also those where I haven't (either form lack of time or simply because I didn't think one was necessary). Regardless of the reason, in all cases, without an agenda, I've found it much more difficult to set the course of the meeting, particularly along a pathway that I would like it to go.
And yet, simply having an agenda isn't enough. We also have to make sure that we are using the agenda for its intended purpose, which is to help us navigate the course of the meeting. An agenda that isn't followed is just as bad as a meeting without an agenda.
In a world where so much is happening at the same time, and where, as leaders and learners, our attention is constantly diverted from one place to another, it makes sense for us to have a little organization, if for no other reason than to make it easier for us to accomplish some of the tasks on our "To Do" list.