One of every traveller's nightmares is missing a flight. This is considering all the time and amount spent to prepare for a trip. It is even more nightmarish to miss a flight while on a scheduled business, conference, or meeting.
Sometimes even if you have planned according to the reporting three hours before your scheduled flight, it might happen that a last-minute unforeseen circumstance(s) such as an accident blocking the highway causing heavy traffic may interfere with your planned timing.