Fantastical is the Mac calendar app you’ll actually *love* to use. Type in that you’ll have “Lunch with John on Friday at 1pm” and Fantastical will schedule it! Or type in that you need to “Buy milk by Tuesday” and Fantastical will create a reminder with a due date!
Fantastical’s natural language event/reminder creation, beautiful calendar, and gorgeous list make it the best calendar you’ll ever use. Stay on top of your schedule with features like native CalDAV support, automatic alarms for new events, iCal and iOS reminder support, and instant search.
I use this product and consider it absolutely essential to my productivity. It actually makes it easier to enter data into your calendar but also, crucially, reduces the chance you’ll make a crucial error.