Worst Airport I've flown out of? SFO! San Francisco!
Well, at least if you are dropping off a rental car that is! It was a maze of hallways and elevators just to get to the tram that slowly gets you to the terminal. Not fun when you are running late! But then again, one time we took a limo from the Palomar Hotel to the Airport and were dropped right at the door and breezed thru.
McCarren in Las Vegas in no picnic either. Especially during a convention when there are an extra 100,000+ people in town. There were over 100 people in line at the taxi stand. Then on the return the security line was the longest I've ever seen in my life!