Ran across my first iOS4 annoyance today and yeah, it's pretty minor. My phone syncs with MobileMe and my employers Exchange server. If I have a birthday set for a contact in Outlook (Exchange) it gets duplicated in my iPhone calendar if I choose to display the birthday calendars. So you're probably thinking, well just turn off the birthday calendar. If I do turn off the birthday calendar, then none of the birthdays I have set up on my MobileMe contacts show up in my calendar.