Virtual clock that counts down to the next appointment with Google Glass

Imagine that you can always see a countdown clock change with Google Glass. There are plenty of people who are struggling to be on time.
Often this has to do with a lack of sound judgment about how much time you need to get yourself ready for departure and timely conclusion of a previous appointment or task.

When Google Glass notices that you will not get to the next appointment in time, a message with the expected time of arrival will automatically appear that you can send to your contact with simple voice control.