The airport train to the city center is the first page of an adventure abroad. Though it is a seemingly mundane element, the airport train sets up the feeling of adventure for me.
I have taken airport trains to city centers in Frankfurt, Munich, Amsterdam, Tel Aviv, Warsaw, London, Tokyo and Rome. Tel Aviv was my favorite in part because I had never been on a train in the desert prior to my visit. My second favorite was probably Tokyo because it had snowed. The flakes added an additional layer of sheen to an inherently beautiful city.
I have missed out on a couple opportunities to take the airport train, such as Paris. I took the shuttle that drops near the Opera Garnier when I first visited the French capital and have chosen it on return trips out of habit. If I ever visit Paris again, I will take the train.
I recommend travelers skip the taxi or shuttle where convenient in places where a train is available into the city. The train always feels romantic. And as a bonus, it costs a quarter the fare of a taxi.