The more technologically advanced you make your web site, the more your clients will see you for the technology wizard that you are. One of the best ways to annoy your clients is to assume that they are all using Internet Explorer (IE) version 7, and then use the most advanced plug-ins available. Since some of your clients are still using an older version of IE, or may even have the audacity of using another web browser like Firefox, Chrome, or Safari, this will give them the extra motivation of taking the time to upgrade to IE 7 just to view your very cool site.
Since all of your recipients are using high-speed Internet services, they want you to test the limits of their e-mail attachment capabilities. A great way to do this is to print out a high-quality document with lots of colors, and then scan it into a high-resolution PDF document. Nothing says “I don’t know what I’m doing” better than a 15 Mb PDF document that has only two pages of content. They would probably send this to their peers as another “Friday Funny,” but their peers’ email boxes would reject it because the attachment is too large.