+Macworld"s +Jason Snell makes some excellent points about ways the electronic calendars could serve us better. Back in the early 1990s when I got first engineering job after college among the first things they gave me was a Franklin planner.

Unfortunately, (or not) I was not a good Franklin user and often missed stuff because I didn't obsessively record everything I did and check my calendar. Without something to remind me where I needed to be, I'd still miss meetings and appointments. Only when I migrated to a Palm III many years later did calendars  really start to work for me. 

While people today complain about everyone constantly checking their phones, at least you can get by putting down a phone and only looking at it when you get a notification. Using a Franklin successfully required constant obsessive checking and recording. 

All that said, Google Now has made great progress in knowing where I am and where I need to be, giving me notifications about when to leave (at last as long as calendar events have sufficient details about location). Incorporating travel time and automatically rejecting events based on that would be outstanding.