I have already written a few times about how sometimes, using Berlin's public transportation system is not a pleasant experience. There is always something that makes the whole ordeal not uneventful. And sometimes, one just needs to have nerves of steel to be able to go through the whole thing.
If none of the typical issues were in play, then I could have just taken a single metro line from the station closest to my house, all the way to the end. However, nowadays, I actually do a slight detour, and take one metro line, followed by a train, just because this is the more peaceful route, so to speak. There are less weird people on the regional train than on the metro.
Sometimes, however, it is unavoidable for me to take the U1/U3 line. Somehow this is the most crowded line on the entire system, it seems. And it is full of weird people, not only homeless ones, but also junkies. It really is starting to be a line that requires courage to board.
I do hope that the city cleans this up at some point, because nowadays, it definitely is not a pleasant experience. And if this is the first thing that one sees on one's way to work, then you're essentially beginning your day with a large dose of stress.