Germany is one of the oldest NATO countries. Of course the US did supposedly intercept the Chancellor's phonecalls or emails or something, but it seems like not much ill-will was generated as a result.
Not supposedly, definitely. And I think the fact that they actually did something like this is very concerning and shows two things: they are very deep inside EU computer and network systems, and that they do not truly consider the EU as an ally.
> it seems like not much ill-will was generated as a result
That's because any ill-will at a government level would have been futile and disproportionate. There was public outrage at the wiretapping but largely the general assumption seems to have been that the US intelligence operates freely in Germany. That US intelligence services engage in surveillance against even close allies was an open secret and most likely widely known among German intelligence agencies and possibly the government too.
Historically, Germany post-WW2 existed at the whim of the US, France and UK. The governments of the occupation forces in the territory of West Germany had special legal rights based on contracts pre-dating and superceding the German constitution. Officially most of those special provisions expired but there's nothing in the original contracts requiring any successor contracts to be publicly acknowledged so depending on how much you like tinfoil hats, it's entirely possible that the US still holds a legal wildcard in German law.
And even if the US had no special legal exemptions, what would that ill-will translate to? Germans opposed the invasions of Afghanistan and Iraq but the German government continued to operate as usual, to the point of participating in "peacekeeping" during the military occupation following the regime changes.
Sanctioning the US would be economic suicide. Despite the outrage about human rights abuses, Germany still isn't sanctioning China. Russia got away with various abuses and even political assassinations without actual consequences because Russian gas was an important import. And the US not only dominates large parts of the German economy but also its culture.