Embrace the detours!
Often, when we're writing or telling a story, we dart off on one tangent after another—a practice for which we may feel compelled to apologize. But such mea culpas are altogether unnecessary, as the detours and tangents may be the very paths our stories need to take in order to make the journeys as fascinating as possible and achieve the most satisfying conclusions.
If your characters or plot look like they're veering off road, consider going along with them, as opposed to bringing them to heel. You may very well find you prefer their route and the unexpected splendors it affords.