I found out something really amazing recently in my tree.
My parents met for the first time in south Florida and married in 1955. Their families were unrelated, from different parts of the country and did not know each other at all. Well, in doing my family tree I stumbled on to the fact that my parents are related! Not really by blood but close enough.
Back in the 1720's, two brothers named Allred had their families. One of them had a great-grandchild that married my Dad's GGAunt and the other had a great-grandchild that married my Mother's great grandmother. It took 282 years and a trek from NC to AL to TN to TX before my parents met and married.