When meetings have no predefined goal or agenda. They tend to go overtime and usually digress into semi-related topics that aren't the reason why the meeting was needed in the first place. Most of the people there are completely bored as the conversation now has no relevance to their work and it's just so frustrating as it's burning people's valuable time. On the flip side, I've had some great and productive meetings when there's been a designated 'meeting leader'. E.g someone responsible for clearly communicating the meeting's goal and keeping the conversation focused on that. Bonus points if they actively promote participation from everyone in the room so the conversation isn't hijacked by just a few people. Triple bonus points if they extract any action items out of the conversation and help the team agree who should take ownership of that item after the meeting ends

The hallmarks of a good meeting include relevance to all the attendees and necessity of synchronous, face-to-face interaction. Most meetings fail to live up to these ideals.