An incident tonight in the Man City game brought me back to this. Matheus Nunes went down in an innocuous challenge and was rolling around and screaming, and when the camera cut to him it was very obvious that he had dislocated his finger. Not saying he wasn't genuinely injured, but I've dislocated fingers twice when playing and it certainly doesn't hurt enough to make a grown man roll around in agony, it is more a case of shock when you look at your hand and realise that your finger is pointing at a right angle. I distinctly remember when I did it, it turned to my centre half partner and said something like like "err, this isn't good" at which point he let out an expletive and turned away.
The problem as I see it is players at pro clubs are conditioned from a very young age to go down and stay down if they feel any kind of injury. Not saying it is coached into them, rather they just copy what everyone else is doing which means the problem is perpetuated.