The common (white, I believe) american is possessed about his heritage. On one hand they are so american that they need to show off their flag whenever possible. Or celebrate thanksgiving, veterans day, independence day as if there was never another day to come to eat a dead animal.
On the other hand however one out of three times I told someone I was german the answer was "Oh, great, I'm german, too!" ... Oh really? So you've been to germany? Actually no, but I'd like to go.
For the other two cases you might as well fill in italian, irish, scottish or "half irish, half french".
(I kind of understand why they do it, it's just ridiculous to claim to be something you're clearly not.)
Just felt like adding this to my long list since it came to my mind today and it was something that I have been thinking about repeatedly - every time I came into that same situation.)