Turning off the annoying spamassassin message encapsulation on BlueHost's servers.
Spamassassin is a great spam killing tool. BlueHost offers it as one of the spam protection options on their e-mail accounts. The cPanel configuration interface for spamassassin is a bit lacking. It only has some common, bare minimum options available.
One thing that spamassassin does that is a bit annoying is it encapsulates all suspected spam messages in a new message, and attaches the original message. This is nice for some things, but can be quite annoying when a legitimate message is crippled in this way.
Spamassassin is highly configurable, and you can do this easily. You just have to do it "manually" and not use the cPanel interface.
If you have SSH enabled, the SSH way is probably the easiest.
$ ssh username@example.com
username@example.com's password:
Last login: Wed Feb 11 11:10:07 2009 ...