...in approximate order, so these are interchangeable.
5. After the conversation has reached cca. 5 exchanges (replies and re-replies), your partner might have wandered on to a different topic you mentioned en passant, or just brings up something unrelated in a "by the way"-fashion. However, you can be sure that they would fail to change the Subject: of the email, so you'll end up talking about, say, [what flower you should buy] in an email with the subject ["faulty CD-ROM"]. (Replace phrases in square brackets as appropriate.)
4. You surely have antivirus software installed, monitoring your emails, which will append its tagline saying that the message has been scanned for / tested against / etc. viruses and is believed to be clean. Again, after multiple exchanges, it will produce a long list of such information, which can be longer than the message itself.
3. Taglines again: "Free Animations for your email! Click here!" (IncrediMail animations usually) - AAAAARRRGHHHHHHH!
2. Sticky keys: I don't see why some people rest their finger on a key for 20 seconds just to make their point???????????????????????? If you want to convey irritation or anxiety, it's fine, but then the emotional charge of the message overrules its content, so I'm bound to respond to it feeling irritated. Well, if that's the idea, no problem...
1. Forgotten attachments -- OK, OK, I know, it's so very easy to write your email and then forget to attach what you were writing about. It happens all the time. I'm no exception to the rule. But if you have forgotten to include the attachment in the first place and need to resend, please KEEP the original subject! I will have no idea that the documents for "Subject: Monday morning tasks" are to be found under "Subject: sorry, forgot to attach". (Often, those who DON'T change the subject when they should, ie. point 5 above, DO change when they shouldn't...)
Note, there is a handy reminder tool called Attachment Reminder to go with Thunderbird: https://addons.mozilla.org/hu/thunderbird/addon/5759
Disclaimer: these are very general statements, nothing personal intended!
Any comments?