The genealogy part is more curiosity than anything else. Who were those people, where did they live, where did they come from, what was going on in their lives? Then there was the self-challenge - can I find them and how much can be found?
You find some and then you just keep going, but it’s amazing how much you learn in the process. Mostly history and local histories and what went on in most people’s lives.
DNA leads you to other family members who may have more info, or it leads you to other relatives that you didn’t find in your research. It takes you to all sorts of interesting places, which are places you wouldn’t have thought interesting in the past. As a plus, I’ve met some very nice 2nd, 3rd, and 4th cousins along the way.
As to the ethnic breakdown that has everyone so excited, you have to take it with a grain of salt. This area is in its infancy, it gets changed as new info comes in, and it’s only accurate on a broad level. Plus, people have no concept of time and movement. Yes, you may have had 3 generations of ancestors who lived in the UK, but did they come from elsewhere before that?
The broad categories such as “Northwestern European”, “Eastern European”, “Western Asia”, “Eastern Africa” are pretty reliable. But drilling down to, say, Denmark or Thailand, less so.
There is a dearth of Native American reference panels, particularly from the US and Canada. Native Americans simply do not like DNA tests as a group and they don’t participate in helping to create reference panels. There is still a lot to be done in Asia with different groups. Right now, there’s a lot of lumping in that goes on with Asian DNA.
I worked with a woman of assumed Italian descent who was outraged because her results showed only a small percentage of Italian heritage, but a large percentage of Greek heritage. “We were always told we are Italian!”
Do you think there was a lot of exchange between Mediterranean groups? Do you think they moved around and traveled back and forth? Did your ancestors just spring up in what is now Italy, or could they have come mostly from a neighboring population? How long were they in Italy? Three or four generations? More? What about their spouses?
People moved around, borders changed, plagues and wars displaced people, new people moved into previously-ravaged areas. Ethnicity is a moving target in that regard, so don’t get too hung up on it. It will probably point you in the right direction unless you are Native American or Asian, but specificity may not be accurate or may be only partially accurate.