What tops it all off for me is when someone interrupts me when I writing a program or troubleshooting a server and asks the brilliant question "So what's up with all the spam I've been getting lately?" I only have 30-40 users, the filters stop ~3000 messages an hour, and I get interrupted and lose my train of thought because someone is getting 3 or 4 junk mails in their inbox a day.

Then there is the person that tries to send an email that gets blocked at the recipient's end with NDR. When I contact the recipient's IT department they're too stupid to make any sense of it. Even though the problem didn't occur until they upgraded their mail system, they claim it's on my end, ignoring what the NDR says.