Some people have no consideration for others' time --knowing full well that "time is precious" for "everyone"--.

In productivity term, 100 people wait 10 minutes for someone -- that's 1,000 minutes (over 16 hours or 2 days) of work lost! How much the meeting cost --in lost productivity--? Often, enough meetings are just used to "communicate" ideas, changes, or to "advertise". Other media can do that much effectively and without "losing work time" --email, memos, notice board, ... save time and other hassles ;-)