I love airports. The people watching there is just phenomenal.
I always get to my flight like 4 hours ahead of time just to sit in the busy concourse and watch the people. They're fascinating.
It's interesting to compare a European perspective with an American one.
In the US, the train stations I've seen range from unremarkable to downright filthy. The one station I found interesting was New York Penn Station, which I would favorably rate as on par with an average airport.