calendar and annual events
Creating repeating events on a monthly basis is great. You can choose the 2nd Thursday of every month and it is created.
Try to do this with annual for Holidays that remain on specific 2nd, 3rd etc Sundays or Thursdays or....Holidays like Thanksgiving, Veteran's Day, Mother/Father's Days.
It should be trivial to have the same functionality (and consistency) for both Monthly/Annual calendar events