Americans, what is something that Europeans have/do that makes no sense to you?

These kinds of things (see also Hákarl, Icelandic fermented shark) make sense to me in places where food was hard to come by, especially in the winter. It was basically once a choice between eat this half rotten thing or starve to death.

Fast forward to now and something that was once done for survival is now a kind of cultural point of pride.