A couple of usability problems when burning audio CDs:
1) It's easy to accidentally add files twice to the CD. Select the files in a playlist, right-click and choose "send to / CD, DVD, & Handhelds / D:, and they are added once to the CD. Then click the "burn CD" button in the lower left corner, without unselecting the files, and the same files are added again. I suppose this isn't how you're supposed to do it but it seemed like the intuitive thing to do, especially when you're adding files a few at a time from different locations and then you decide you're done and you want to actually burn them.
2) The duplicates wouldn't be such a problem if I could easily remove them from the CD. But when I list the files that will be burnt on the CD and I select the duplicates and press "delete", both copies of the files are removed from the list, leaving me with an empty list.