I just found out about a server crash at a friend's old company. It seems one of the staff members sent a 2.7 MB graphical file (wrapped in a PDF, wrapped in a MIME email) to 900 people. For some reason, that crashed the Exchange server creating 8.5 GB of transaction logs in just under 20 hours, which overflowed the system drive, which caused the entire server to collapse. At last report, a consultant had cleaned out the transaction logs and most of the message queues, but Exchange was still re-trying some of the addresses.
This problem was, therefore, between chair and keyboard. Whose chair and whose keyboard is difficult to tell.