Cancellation subject line
When somebody sends a meeting cancellation, the word "cancelled" is not shown in the subject line. It just says the name of the meeting. As a result, I have no idea that the meeting was cancelled.
In general, when somebody sends out a change to a meeting, it's very hard to tell what the change was. Again, I just get an email with the meeting name as the subject line, and there is no clear indication that anything changed at all, let alone the nature of the change (time, place, etc).