A bus driver's offhand comment fixed my chapter ending problem

I was riding the 42 bus through Minneapolis last Tuesday, scribbling in a notebook like I always do, trying to figure out why my mystery novel's final chapter felt so flat. The driver announced a detour over the intercom and said "sometimes the long way home gives you the best view." That hit me differently. I realized my ending was too neat, too direct. I rewrote it so the detective takes a wrong turn, talks to a witness she dismissed in chapter 2, and the real clue is in that conversation. It added maybe 400 words but the payoff finally landed. Has anyone else had a random overheard line untangle a plot knot for them? What did it cost you to follow it?