I almost fell in a fast-moving stream on my last hike (totally my fault for not scouting first). Now I research seasonal flow rates before any trip, which saved me on the Deschutes River route.
Ever hear about the guy who avoided that washed out trail in the Rockies last spring? He saw the closure notice online because he checked the forest service site right before leaving. I guess sometimes the scary close calls happen to other people so we don't have to learn the hard way.
Wasn't that trail closure actually from two springs ago? I feel like that story gets told every season but the details shift. The real lesson is just checking right before you go, like @hugopark's friend with the creek flows. My buddy did the same thing last fall with a fire closure in Oregon. Saved him a five hour drive for a locked gate.