Meetings are ok if they have a clear agenda, a goal what should be decided in the meeting and a small focused group of attendants. If all this is true meetings

Meetings are ok if they have a clear agenda, a goal what should be decided in the meeting and a small focused group of attendants. If all this is true meetings can be very helpful to get some decisions or a better common understanding for a project. However often meetings are called in without a real goal - just for the sake of having a meeting. Or a large group of people is invited which don't necessarily contribute to the outcome. If any of those are true the meetings can feel like a giant waste of time for the participants. If people feel they are in a waste-of-time meeting they start working on other things in it, e.g. replying to email, .... This makes the attendant group even less focused and the decreases the outcome even more. These kind of meetings often happened to me in bigger projects in corporate environments, where there were weekly meetings scheduled for almost everything.