One of my clients wanted to be able to send an email "blast" to all 50,000 of their customers via their intranet application. They wanted to be able to include

One of my clients wanted to be able to send an email "blast" to all 50,000 of their customers via their intranet application. They wanted to be able to include an attachment with the email. I wrote the code and told them it was ready. A frantic call came in at midnight. The whole email system was down. Unfortunately they had attached a 2 MB PDF file to each email. So our little underpowered Exchange server was desperately trying to send 100 GBs of emails downs our T1 (plus dealing with all the bounce-backs).