One thing I like is trains. Perhaps partly because of the more controlled nature of them as opposed to cars or planes. The other thing I like is the opportunity they afford to people and scenery watch, because all you have to do is pay attention to which stop is yours. And train stations, at least in Europe, are quite interesting. (some in the US are, too, and I haven't seen as many so I can't make a broad generalization, but the ones in Germany, of which I can most speak to, are quite interesting)
I was in Berlin for a couple of months this summer, and it was the longest I've ever spent in a single European city (also the longest I've spent in most any major city in the world), so I got a chance to get pretty familiar with the U- and S-Bahn system. And every U- and S-Bahn station was different, which I loved. The one at the Zoo was painted with animals. One was fancy and marbled because it was remodeled with marble that came out of Hitler's palace when it was demolished. Some had quotes decoratively painted or tiled in them, some just had interesting paint or tile patterns, some had more complicated mosaics, some had more ornate arches and things, and some were still old and restored because they had been 'ghost stations' all throughout the division of Berlin (which meant they were shut off because they were in or under no man's land near the Wall, thus they sat vacant for some 30 odd years). Then there were the brand new ones that are the beginnings of a new line still under construction, and those had photos of various historical train stations.
There is a lot that can be said by and in a train station. And I like to think about all the generations of people that have come through them, all the trains that have come through them, and all the history and life stories they have been part of. The secrets they hold, and the secrets held by those traveling in them. Especially, to me, in a city so fraught with history as Berlin. To see the photos of the old stations, and to see photos in some of the 'ghost stations' from that time, to smell how they still have a slightly stale air, to wonder what they were like all empty and shut up and how many people snuck into them, makes me feel connected to all the people who saw them before me and who will see them after.
It is amazing how many different people one can see in a city so large, even when one's train riding routine is about the same. Always different people, and always so many languages. One can see the city at night, when the sun shines, when it rains, (and when it snows, although it did not snow during the summer). Life and activity and hopes and dreams and fears all around, carried around by the trains. I do love trains.