I think we Europeans as a diverse society have far less willingness to give up basic rights than those in the US.
Public sentiment does sway sharply in the aftermath of events like 9/11 (or, in our cases, 7/7 in London and the like). We sometimes tolerate nanny state behaviour and suspending basic rights and freedoms more than I personally would like following such extreme, high-profile events.
However, even then, public sentiment seems to sway back again much faster here. Just look at the level of public concern over a tiny number of high profile deaths in the UK in recent years where police were involved, or look at how sharply Google have been slapped down over privacy in places like Germany. I think this is probably down to having a lot of very different cultures who have come together in their common interest but never merged to the extent that the US is a federation of relatively similar states. Consequently we have a much broader spectrum of political opinions permanently in play here and it's much harder to permanently overrule many years of history and precedent without someone objecting loudly enough to slow things down and force more debate.
There seems to be an inherent tension between recognising that the US is often a useful partner in economic and military matters, and recognising that we must not act as some sort of junior partner to a country that frequently gets big issues spectacularly wrong and that has a demonstrated history of screwing its partners whenever its own interests dictate.
My sense is that the US has been cut a lot of slack in recent years because of its economic strength and 9/11, particularly when we had Blair running the show here in the UK, but that public patience with the one-sided deals and all the silliness we have to put up with as a result is now rapidly running out as we have our own problems to deal with and the US are getting in the way or indeed causing some of them.