I’ve been to quite a few airports in my life, and one of the worst is definitely Dulles International Airport in Washington DC (actually not in DC but that's the least of its problems). No comprehensible signs, long lines leading to nowhere, unhelpful, clueless employees, overcrowded halls and general chaos. It took me over 3 hours to get on a flight to Toronto.
Of those 3 hours in the airport, I must have spent 2 and a half hours on a variety of wrong lines (which I was TOLD to stand on). The other half hour was spent wandering around the ground floor where the bus lets you off (at a back door with no signs indicating where to go from there), only to find that the flight to Toronto was upstairs.
So if you possibly can, avoid this airport. Fortunately, there is a choice. If your destination is anywhere near downtown Washington, don't book a flight until you are sure the plane lands at Reagan Airport.
DC was wonderful...we had a great time, except for Budget Rental Cars Dulles Airport location. We were given a dirty car with dents that smelled horrible. The dents were noted with small red stickers which would indicate that the counter was aware of the damage, yet after we returned the car the manager claimed that we damaged the car and tried to bully us into signing a fraudlent accident report. When we refused they put a $500.00 charge on the card used to secure the rental. The customer service department has been no help at all and we have had to complete paperwork to dispute the charge through our bank. Don't be a victim of Budget Car Rentals Dulles location and it's unethical manager Monica Shere.
Dulles Airport! United Airlines loves Dulles, but I understand the locals didn't until recently. It's a very pretty airport as you approach by car, but can be confusing once you are inside. Follow the signs carefully to get where you are going, and make sure you take the right shuttle to the right terminal or you will be lost! Also, after I checked in, there was a big sign with gates posted for flights...this sign was dead wrong. If you are unsure, ask someone to verify your gate.
Walked everywhere freely at night & felt extremely safe even when I was lost, which was often. Bags were stolen at the airport, Dulles International, however & never recovered. Really personal night bags that should not have been attractive to anyone except that they were easy to lift.