I think part of the fun is summed up in the old network command, and question, “whoami”. Who you or I are is dictated by the choices we make, but also by the reactions we have had to the choices our parents, siblings, and other determining people in our lives have made, positive and negative. Whoami is a network command that tells a computer network user who they are on a network, and what parts of the network they can access. When you begin to look at what and why your grandparents and other family members did, and when, then you understand a bit how they understood themselves, and you begin to understand yourself, and even if you don't understand or sympathize, empathize with them and why they did what they did.
Part of it is that many of us have a hunting instinct, whether we actually enjoy hunting, shopping, or looking for hard-to-find objects, or just like the challenge of finding something that has been lost. The challenges of putting facts together like you would a jigsaw puzzle, organizing data so it makes sense, or just arranging information so it is complete can be very gratifying.
One example of this is when I found a great-grandmother's maiden name on a death certificate. It was Scandinavian in origin, Lundene, but did not make sense when used as a surname, especially in a Norwegian context. There are Norwegian, Swedish, and Danish people with the surname Lund, and some Swedes have the last name of Lundin, or similarly spelled versions of Lundin, but not “Lundene.” Lundene means “The groves.” So there are many people with the name of Lund, but not the Lunds.
By twisting and tweaking my searches, I was able to find family members in the U.S. 1880 Census with that surname living next door to other family members with an even more unusual name, Jeglum, so they were fairly easy to find. All I had to do was look next door. I then compared both families to an 1870 document. The Jeglums were there...but the Lundenes were listed under the surname Lund, with the same first names as the Lundenes in 1880. That was my clue that the family had undergone a number of name changes. When I searched back ten years before, I found the family under the surname Knutson, on par with how they would be named in Norway, using the father's patronymic as Andrew, or Anders, the son of Knut.
This then gave me further clues about where and when the father, and the mother, Olea were from. It even lead to other relatives’ family trees, where a wonderful picture of their beautiful family, all ten family members. It’s fun having lots of relatives, isn’t it?