I think there's something to be said for those times when you line up a good location, a good model and all of the right gear.....and things go a little differently than expected. Yes, unexpected obstacles are a good thing. They certainly don't feel like a good thing but why not use them for a positive purpose?
I recently put together an impromptu gathering for some members of the Photographers of San Angelo group in the form of a sunset shoot atop an earthen dam. It's a great spot -- easy to get to and it affords a wide view out over the landscape. Unfortunately, the weather didn't feel like cooperating. The temperature took a very sharp drop from the comfortable level we had around mid-afternoon and the wind picked up to an unbearable 25mph+ sustained with higher gusts. Samantha, our brave model, did the best she could to bear the cold and wind for the duration of the shoot. Setting up lighting gear was near impossible. In that kind of wind, absolutely everything becomes a sail. Still, the Setti dish went up on a light stand with some heavy weighting and under the watchful eye of a photographer who didn't bring a camera with him.
We all made the best out of the situation but when it came time to download the images into Lightroom, I could see that many of the photos weren't turning out as well as I'd hoped. It was no fault of our model -- she did an excellent job under extremely challenging conditions. Our group received a harsh lesson on the unpredictable nature of weather and the importance of having a solid alternate plan to cope with unexpected circumstances. It was a cold and windy experience but made us a little more aware of how to avoid these situations or deal with them if they can't be avoided. All in all, a net positive.
The story does end on an up note. The ratio of "keepers" to throw-aways was a little skewed toward the latter but there were some nice photos in the set that Samantha ended up liking quite a bit.