My family will celebrate our 40th annual reunion this year. Now that my kids are attending, I'm seeing the tradition's full impact.

The author's family will celebrate their 40th annual reunion this year. Courtesy of Lindsay Karp I grew up going to a big family reunion every year. It's always felt like a celebration, and as my life changed, attending was a familiar comfort. Now, I bring my two sons, and I've realized what an impact the tradition has had on my life. For as long as I can remember, we spent the Saturday before Father's Day with our extended family nearby at my cousin's home outside Philadelphia, swimming,...