WHEN Jeryl Brunner, a writer in Manhattan, was in her 20s, she had a friend who was just the sort of acquaintance people scoop up in their social net when they are young and trying to carve out a life in a new city. The friend was fun, outgoing and stylish, and always up for a night of dancing at Area, or a weekend jaunt to a Neiman Marcus outlet in New Jersey.

But as Ms. Brunner neared 40, the reasons for their spending time together became less clear. “It’s almost like we were in different movies,” said Ms. Brunner, now 46. “We didn’t connect on this fundamental view of what was important. I don’t obsess about material things. I’m the kind of person, if I had $100, I’d see a play; I’d have an experience. Her sense of joy came from owning a Gucci bag.”

She decided it was time to let her friend go. So Ms. Brunner took the “bad-boyfriend approach” and just stopped calling. After the friend made a few spurned overtures — and after some awkward conversations about why Ms. Brunner was always too busy to get together — the friend got the hint. Years later, however, the breakup still feels unresolved.

“I wish I would have handled it differently,” Ms. Brunner said. “I think you owe it to that person, rather than keeping them guessing.”