It works when you're walking up the trail and you tell your daughter to watch her step. "I told you so."

It works immediately after that when she tells you to duck under the branch. "I told you so."

It works when you get to the summit and the sunset is awesome and your daughter has her good camera, but you don't have yours. "I told you so."

It works when you totally see a goat on the upper ledges and everyone else says it's not a goat. "I told you so." (It was totes a goat.)

And it works when you get back to the trailhead for the last afterwork hike of the year and your daughter says she enjoyed the trip. "I told you so."

See? It works all the time. Magic.