Regarding the more colourful or strange members of certain communities: remember that in past decades with the spread of the 'burbs, inner city areas were long where cheap and sometimes run down accommodation was easily available to those who needed it, including a criminal element. As these parts have become more and more trendy and attractive to a lot of people, it has kind of squished a certain element of society into smaller spaces. A lot of those people often add to the cosmopolitan feel of some inner city neighbourhoods - I remember that years ago I loved being close to Brisbane's Valley area because of that as it seemed a very exciting and exotic part of Bris to live. I never would have walked alone anywhere there at night (and certain areas even in daylight) in a blue fit mind you. Not defending the existence of crooks - just maybe why some areas might seem to have more odd-bods than others.
Not very well worded sorry - hopefully you get what I mean.