Well, in New England, California, Colorado and a few southern states you can actually marry your first cousins. My father's family came from a small area around Bethune, CO that was known as "The Settlement" where a group of Germans from Russia who came from the Bessarabian village of Brienne established a colony. They are very inbred - I can remember visiting as a young woman and hearing a young man discussing how he had married his high school sweetheart after all. It seems he had decided to attend the community college over in Stratton to try and find a spouse he wasn't closely related to, and when he came home with the girl he met there, his mother pointed out how they were all related. She was more closely related than his high school sweetheart, so he decided to go ahead and marry his high school sweetheart.
Nothing like visiting and finding that everyone in town is related by blood or marriage or both. My mother was seen as very exotic and "foreign" due to her having Mayflower/Jamestown/Hueguenot refugee/American Revolutionary soldiers/Colonial American ancestry..
LOL- when we discuss dog pedigrees at some point a newcome will decide it's like a small town. We introduce the dog by who they're related to. In most cases we can go back quite a bit and explain who the ancestor is also related to, what everyone did, who had puppies by whom. It can get very involved.