I used 23andMe about 4 years ago. Results are still updating and refining. I found out some things I didn't know, and other things I knew or suspected were confirmed. I even got a couple of surprises. One is a grandson of my father with a woman he had an affair with before he met my mother. They had a daughter who had children. I found that in addition to my family he has 4 more grandchildren and 8 or 9 more great-grandchildren. My mother knew about the daughter, my half-sister, but it's a good thing my mother never knew about the grandchildren and great-grandchildren. She would have hated my father all the more.
Yes, we laugh about it in my family.
There is another man who comes up in my DNA Relatives list as a first cousin or half-nephew, sharing 12% DNA with me. I've communicated with him, but neither of us has any idea how we are related. I suspect it's through one of my father's brothers. Those 3 boys couldn't keep it zipped worth squat.
Yes we laugh about that too. We're a jolly bunch.