One useful Microsoft Outlook setting for self-protection is hidden in Tools > Options > Email Options > Read all standard mail in plain text. If you switch this on, all HTML emails will appear on screen as plain text, thereby protecting you from harmful HTML code. This is great if you get lots of dodgy HTML emails because it prevents you from inadvertently clicking on something you might later regret.
The trouble with this approach is that it also removes all the lovely formatting that the email sender may have used to make their email a pleasure to read. And if, like me, you use formatting (like bold and colours) to draw attention to important bits of your email, you need to bear in mind that the emails you send may end up looking very different when they are received. So think carefully about how you use formatting. If your recipients read their emails in plain text, then ye olde formatting like *asterisks* and CAPITAL LETTERS might work better. Even if they are rather ugly 🙁
Of course, if you decide to set Microsoft Outlook 2003 to read all standard mail in plain text, you can immediately restore the HTML view by clicking on the message title bar at the top of any email that reads "This message was converted to plain text." and choosing Display as HTML.