Lack of respect for truth. Scientific, political, business, personal...all webbed with lies these days (maybe always, I don't know, but it seems worse).
There is so much lying and outright falsehoods being told, about anything you can think of, to advance someone's agenda, that truth is just a sad remnent of itself that is cast off in a corner. It holds little to no power anymore, because even when truth is told, someone else will just lie and say it isn't the truth, and well, since there are so many lies, who's to say what truth really is anymore.
I'm not saying this is unique to America, as I don't live somewhere else, but I think we are very good at it. Very good. To our detriment, I believe.