And I'll one-up you on HTML email. I used to regularly get email from a guy (a marketroid at an old employer) that consisted solely of Word docs. With no special markup or anything -- just text. And they'd be multiple megabyte emails. For two sentences.

This is becoming common, unfortunately. I'm still fairly "old school" and don't think
email should have HTML or attachments. That's what webpages and FTP
are for after all. (But I realize that I am in a very small minority and have lost that
battle half a dozen years ago.)
But I can one up your story. A few years ago a friend sent me an email with
a 4 or 5 Meg attachment (substantial size for late 90's slow modems.)
It turned out to be a PowerPoint document. Since I received it on a Unix
workstation, I had to try to read it under our PC emulation. Of course, it
used the just-released version of PowerPoint not installed on the emulator
image yet. So I laboriously modemed it to a PC at 28.8 kbaud.
After much time and effort, it turned out to be a 1 page image which was a
party invitation. I converted it to a 50KB GIF file and sent it back to him
asking more or less "what's up with *that*, Dude?"
Turns out he had humongous bandwidth at work, assumed everyone was
running PCs with PowerPoint and had no idea that his simple image was
MS-bloated into multiple megs.

Ah, the perils of "all the world's Microsoft" thinking for those of us who aren't.

Anyway, my email filters discard anything over 100K now.
People that email me understand that.

On a related note, many email services (like American Airlines weekly specials)
don't even offer you the option of getting their email notices in non-HTML
format any more. I mean, why send 2K of destinations and fares, when
100K will do (worthless images and markup code that never change from
week to week).