This is not meant to be an exhaustive list, of course.
1. bahn.de is not as cool of a website as idos.cz. But the ads are better.
2. Giessen is a nice-sized city: just big enough to be interesting, and small enough to be cozy.
3. Street musicians in Germany are often really good at playing their instruments. I heard some awesome traditional-style accordion playing today as well as a woman who was tearing it up on "Fuer Elise" on her portable keyboard.
4. There are a lot of people speaking English on the streets of Giessen. A lot.