Dual US/EU citizen here, so a good bit of experience. I think the key difference in my experience is that the EU only asks questions past immigration and in customs, and mainly about what you're carrying.

When I come back into the US, I'm asked at immigration about my actions, what I've done, where I've gone, why I've gone where I've gone, who I went with, who I met, what address I'm going to in the US, etc. And if I deign to get smart with them, that's a 30 minute tear apart of my bags/more thorough interview of my "actions."

EU? Show immigration officer my passport. Receive either pleasantries or a nod and am sent through. I might be stopped going through the green lane and asked to open my bag, but this happens maybe 1 in 50 trips. The end.