My problem with all this discussion on post-processing is that in street, what matters is what’s in the image, not how technically perfect the image is. I’ll grant you that if you’re doing landscape, or nature, or wabi sabi, or the kind of urban work Slobodan does, having a technically perfect image matters. In street, what matters is whether or not the picture conveys something significant about (to use a cliché) the human condition.
There was a time when I could use Photoshop to do all sorts of things. I’m now 89. My eyes aren’t as good as they once were, and I’ve forgotten a lot that I once knew about post-processing. But I still can tell the difference between a decent street shot and one pretending to be street, even if the pretender has been post-processed to perfection.
I agree with those who’ve pointed out that the condition of the picture ought to be at least somewhat consistent with the scene it presents. If I have a picture of a gritty scene it’s not unreasonable to preserve “features” like noise, which reflect grittiness and that the picture was shot quickly and in passing. Remember that HCB’s wonderful book, which pretty much defines the street photography genre, originally was titled “Images à la Sauvette,” which translates roughly as “images on the run.” Doesn’t hurt to let the picture make clear that it was shot on the run.