Paul Durden (movie twin town) once said Swansea was a 'pretty shitty city' He obviously hasn't seen port talbot. The town is dingy and uncared for looking. The people are worse, about 20% are genuinely 'not right' Seriously, they not only look odd but act it as well, about another 20% are borderline, it's really scary that that many odd people are in one place.
I can't work out whether it's pollution from the industry all around it, or inbreeding. I don't mean sleeping with your sister, but in fairly small communities it's not uncommon to end up marrying a cousin or similar, this dilutes the gene pool.
Take Tesco in Port Talbot for example, about half the people in the shop aren't actually shopping, they are standing around staring at the ceiling, or worse standing in big groups blocking the aisle and having a gossip, or my favorite they come to a door and just stop dead.
It actually has a name, it's called the boundary effect, it's what happens when primitive people come to a change of environment, in modern people it's all but gone as we know what the environment will be when we go outside (or inside), but that wasn't taking into consideration the people of port talbot.