...you learn too much about your family:
Thomas Holbrook, born in England 1601-2, had two wives: Experience Leland, who died in England, and Jane Kingman.
By his first wife, Thomas had Anne, who married John Reynolds. Their daughter Mary married Benjamin Burdick, and had David, whose daughter Lois married Benjamin Pendleton, the father of Jabez Pendleton, who married Sarah Dunbar.
By his second wife, Thomas had William, whose daughter Mehitable married Jonathan Sprague, and had Joanna, who married John Tefft, whose daughter Mary married Benjamin Barber, who had Nathan, whose daughter Eunice married Thomas Dunbar, the father of Sarah Dunbar who married Jabez Pendleton.
Which makes Thomas Holbrook simultaneously Bob's Tenth Great Grandfather and Eighth Great Grandfather (and makes Jabez and Sarah half-fourth cousins, two times removed).
When we tried to figure this out we discovered that Bob's 8-Great Grandparents Samuel Hubbard and Tase Cooper (who incidentally were the founders of the Seventh-Day Baptist Church of America) had two daughters, Ruth and Bethia.
Ruth Hubbard married Robert Burdick and had Benjamin, who you will remember had David, whose daughter Lois married Benjamin Pendleton, the father of Jabez Pendleton, who married Sarah Dunbar.
Bethia Hubbard, on the other hand, married Joseph Clarke, Jr., whose daughter Judith married the Reverend John Maxson, who had John, Jr., whose daughter Thankful married Nathan Barber, who you will remember had a daughter Eunice who married Thomas Dunbar, the father of Sarah Dunbar who married Jabez Pendleton.
Which makes Samuel Hubbard and Tase Cooper simultaneously Bob's 9-Great Grandparents and 8-Great Grandparents (and makes Jabez and Sarah fourth cousins, once removed, in addition to being half-fourth cousins, two times removed.)
All of that can give you a headache.