There is a big nowhere-land between street art and that soulless smearing you will find in the streets. If you like to document the actual state of your surrounding environment you can point your finger at things that should not exist like dog poo, waste and other things that will feed the broken windows theory.
Many foreign visitors think that Germany is a nice and clean place to live, but the reality is that there are a lot of places full of waste, cheap graffiti and vandalism. The most extreme spot is the Sternschanze (and surrounding) district where the streets are full of dog turds and stuff other mindless people have thrown away. For me as a photographer it is also important to point my "camera eye" on this serious deficit to show it to a wider audience.
The most awkward thing is that this kind of decay is attracting people with a good income (working mostly in media) to live in areas like this, paying high rents and wearing expensive clothes.