I chose "unreadable", but for an odd reason. I use Mail.app on OS X, and its built-in junk filter is impressive. However, it seems to be less effective at processing and interpreting Japanese and Chinese, so sometimes one of those will get through. Since I read neither, most that I get is 'unreadable'.

Plus, I'm not sure how to tell the filter "If you see something that looks like a goat next to a sparkplug". And while I don't mind learning something of other languages and cultures, this is not the conditions under which I'd like to do so.