1. If you enable XP Styles, do so everywhere. 2. If you label a group "Today" - put today's items in it. 3. If you're going to make your options dialog look like system dialogs, don't cut corners. 4. If you clone the Outlook 'look' - go all the way. 5. If you display a language for no apparent reason, at least display my language. 6. If you use http - don't do it on the GUI thread. 7. If your application has settings, save them when I press apply. That way I won't have to re-enter them when your application crashes.