Who said anything about being angry? I'm merely pointing out that today's society is OTT with H&S. The company I used to work for would get people trying to sue them for the most ridiculous of things.
As for the nail situation, these things happen, has it been rectified since? If it has been managed then I see no major problem here. Have you never had a anything come loose at home? These things happen, although usually over a longer time period, which might be why you're having an issue with it in which case I can sort of see your point.