This example looks a bit marginal.

• Midgar in Final Fantasy VII approaches this. The slums at least.
  • The city part of Midgar is actually quite civilized, with Shinra security patrolling the streets.

I never got it. If it's a "wretched hive of scum and villainy", why does Obi-Wan drink there? I wouldn't walk into my local and say "What a wretched hive of scum and villainy", even if it were! For one thing it would be horribly rude and for another, I'd probably get a clip round the ear from the barman.

Why is 4chan not the page image? It really is the best example. People are going to understand the trope insistently with 4chan, but right now you have to read the caption to understand. Also, most of the links here are from 4chan.