A few from my RT mail queue:
I always particularly enjoy the ones with no data in the message body.
Subject: "Unable to open excel file"
IT: "That isn't an excel file."
User: "I didn't realize there were other kinds!"
Subject: "Can't send any email."
Body: to anyone. Not even the help address.
User: "Oh. It's working now."
Subject: "Is the server down?"
IT: "Can you please be a little more specific? We run a large number of services. What is it exactly that you're currently unable to do?"
User: "I don't know. It's down. I can't get at any of my files or anything."
IT: "Ok, I think the best thing is for me to come and see you. Can you please tell me which office you're in?"
User: "Oh, I'm at home today."
IT: "Ah, so the problem is with our remote access portal. Are you getting any error messages? It seems to be working from here."
User: "What's that? I just took the PC from my desk home with me last night and now nothing works."