Not every obstacle is secretly a gift, and pretending otherwise is exhausting. What's true here is narrower and more useful than that.
A road closure sent a friend down a side street for three weeks. She now takes that route by choice — it's four minutes longer, it passes a bakery, and she's measurably happier in the mornings. She'd never have found it voluntarily.
The obstacle handed her nothing. It removed the default, and she paid attention to what was left. That's the mechanism, and it's a modest one: blocked paths force you to actually look. Whatever's blocked for you right now, look sideways once.