The EU is very sporadic. I walked straight into Sweden from a flight from Iraq and customs was not even there, and passport control waved everyone through with the most cursory of glances.

I'm not sure the customs official knows where you came from (unless they explicitly ask, of course), because in my experience normally you get off the airplane and join a common queue. I think your passport counts a lot more when it comes to how strict the scrutiny is going to be. I'm assuming you're American, if you had an Iraqi passport, maybe you would have to answer a few more questions.

Not the EU, but I once accidentally entered Switzerland in the Zürich airport. The passport counter was unmanned and the doorway next to it was open, so I assumed there is another checkpoint somewhere further.

When a guy started chasing after me 30 seconds later I realized my assumption was wrong. But there really wasn't a way to know.