When I upgraded from Pegasus to Thunderbird as my email client the one thing I really really missed was the neat way Pegasus would look for words or parts of words like "attach", "enclose", "file" and ask me "Did you mean to have an attachment?" if there was no attached file.

Now Lifehacker mentioned an addin for Outlook users to achieve the same thing. In the comments I found that there is one for Thunderbird.

So, missing attachments should no be (almost) a thing of the past, again, here in the future! I've seen the future and at last it works - as well as the past ;)