I noticed a difference in how Google Calendar and Outlook handle recurring appointments, specifically ones that are on the end of the month. If you try to schedule an appointment on the 31st of every month in Outlook, it will put your scheduled appointment on the last day of the month, whatever that is.
You'll even get a message saying so:
In Google Calendar, scheduling an appointment on the 31st of every month means it will only appear on those months that have 31 days. Google doesn't provide any type of message about this.
So, while Google sticks more closely to what the user's request actually was, Outlook applies a little bit of interpretation and assumes you want it to run every month. Which of these approaches do you think makes the most sense, and why?