Frankfurt Airport is one of the largest and busiest in Europe, and the airport, especially the transit lounge is huge and quite crowded.
The concourses, A B C D are four corridors, which all converge in a central hall which has got restaurants, shops, kinos ( blue-film video stations), and bars, as well as huge lounge where you see hundreds of people sprawled on very comfortable, stretch-back kind of chairs.
If sometimes, a few flights, even 2 or 3 (which rarely happens) then there is chaos, the crowds get larger, and not enough sitting space in the central hall where everyone wants to be.
Frankfurt is a big city, centrally located on Rhine riverbank. Up north you have Dusseldorf, Duisburg, Hamburg and down south you have stuttgart, Cologne.
Frankfurt mainly is a commercial/business area, not much of tourist attractions. It’s a rough place, especially the Hbf area which it’s better to avoid. You can stroll around in daytime, but dont take a hotel there, Suburbs away from Hbf are much better. Inner city rail link is excellent.
As Usual, Germans are gruff and unsmiling, but once you establish a rapport, then they are ok. Langauage is a poroblem, but big cities like Frankfurt, one can manage with English. There are plenty of Indian restaurants too, since German food is anyway not acceptable/palatable to Indians, Chinese and other oriental restaurants too are good.