Usually, using a standard dialog is a great way to save code and maintain a consistent user interface. However, some of the Palm OS standard dialogs could use a little more customization that we provide.
A good example is the SelectDay dialog. This is a nice UI, letting you pick a day from a calendar view. As a shortcut, there's a "Today" action button that selects the current date and exits the dialog for you.
This works well except for one context: in the prefs, the SelectDay dialog is used to select the current day when setting the date and time. So, if your date is wrong and you hit "Today", you'll still be left with the wrong date.
This doesn't trip people up too much, but it is a little user interaction glitch, and an example of where using a standard component doesn't give the exact fit needed.