Truth be told, I think the US was great all the way till shortly after Bush allowed 9/11 to happen. The American people actually united and came together. It's sad that it took war felon Bush to allow 9/11 to happen for Americans to come together like that.
Since then, however, Americans are more divisive and polarized. The economy has collapsed. The middle east is destabilized, thereby making the US (and the world) less safe. The US is not as respected (but I feel Bush is more the reason than Obama for this). Now people are crapping on police officers and on the war veterans. Furthermore, we have to choose between Trump or Hillary. These have not been America's greatest days whatsoever.