My parents are the only Dangling Threads in my life. I have a few others as well. Whether or not I choose to tie up those threads depends on a number of factors.
Around 7 years ago, my (half) sister decided to try and tie up her loose ends with me. We had grown up together on and off (mostly off), and managed to lose track of each other when I was in High School. My dad had long divorced her mom. Sis had her own family to be a part of. Dad didn't do a great job of keeping track of her either. Anyway, she ended up being in Europe around the time I was for work, and so she made arrangements to come up to where I was in London and hung out with me for a weekend.
Right around that same time, my best friend and I drifted apart at a very critical time. I was trying to get him to come to my wedding as my best man. Keep in mind this is a person I'd known since the 6th grade and we had always been close friends. But for whatever reason, he chose to choose that time cut off all contact with me. No explanation, not even a "eff ewe." To this day, I still don't understand it.
Meanwhile, contact with my sister also meant contact with my step-mom, who was fairly close to me when I did live with her. Getting in contact with her was a wonderful thing just because she was—and still is—a wonderful lady. For a while there, she was sending my kids birthday and Christmas gifts. Ironically, it's more than any of my blood relatives do.
Meanwhile, I only occasionally have contact with my sister. I think she shares that Welch trait of being inwardly focused. She seems to have survived her own childhood well-adjusted. Conversations I have with her, when they do happen, are pleasant and natural. Her step-father was, in many ways, like my mother. I experienced some of his venom first-hand. I can only imagine what she experienced having lived with the dude for a decade or more.
One other dangling thread to mention is a close friend I went to college with. I stopped seeing this friend maybe a couple of years ago because it became increasingly difficult to "be around" this particular person because he was so self-absored in his pity about his particular situation—not having a "real" job, living at home with his parents, and having a crappy girlfriend. This was in sharp contrast to me having a stable job and living in my own house with wife and kids. While we never discussed it, we just mutually "let things go." A mutual friend called me recently and I hear he's doing a lot better—has a gig at Cisco and is on the road a lot. Still living at home, if I remember right, but he's supposedly saving his money for a new place.
I guess what it comes down to is that just about every blood relative I have and two of my good friends are dangling threads in my life. I am on good terms with most of my living blood relatives that aren't my children. I do not believe there are any issues there. My parents are a different story, but I don't think there is much I will be able to do there. I have made peace with that. My kids, weil, I've got a lot of time before they leave the nest. For my two friends, I have a connection to one of them thru a mutual friend. I can track him down if I feel the need to. The other—my former best friend—I have no known connection to.
There is a thought here about being inwardly focused and how that relates to how many dangling threads you might have in your life, but I have an inability to express them correctly at the moment. Maybe because it's almost 2am and I should be sleeping.