Every time I use a calendar "app" I mourn the regression from 80s-era principles of usable GUI. Can I cut and paste appointments? I can not. Can I select and manipulate multiple appointments? I can not. Can I perform search-and-replace in my calendar? I can not. Is there, then, a separation between Model and View such that I may manipulate my appointments in an alternative interaction language such as a CSV file? There is not.
@tonyg (Not to invalidate your general point, but specificially the first ist quite possible in Calendar (formerly iCal), mulitple appointments can be selected and moved (And deleted) but not edited in gegneral; replace is not a thing, too. Your general point stands tho)
@krono You're quite right, Apple's one is epsilon better than, say, Google's one. I feel like there's still a fair element of "faint praise" here :-)