I freelance and often work with US clients. I find Americans tend to be more polite in business matters, however they are also likely to tell you things are "awesome" and "great" regardless, however I have learnt to completely ignore any praise because it will no doubt come with many subtle caveats later.
"Yeah that looks awesome, really great...really great working with you. Could you just change this, and this, and this, and this, and this, and this."
I don't think its because Americans are non-genuine though, just more polite and very equipped for corporate situations.
Oh I know exactly what you mean!
I work at a very large corporation in America, the slightest tiny bit of negative thought on a project will get you your pink-slip (p45) faster than light.
The whole thought-process these people have is very alien to me. If there is a problem, fix it and make sure that what caused it is eliminated so it doesn't happen again! But no - that can't happen because the root cause is a showcase for technology X, and utterly vital to the strategic goals of the enterprise etc.
All the booyas that go on when the slightest trivial thing comes online is unbelievable, they congratulate themselves to an almighty degree if they manage to open a Word document.
It really is amazing