I’m not entirely certain why, but my eye is often drawn to clouds when they’re backlit by either the sun or (preferably) the moon. I like the post-apocalyptic color palette in the below shot, and how grimy the clouds look (and other than a small tweak of the levels, I haven’t done any post-production on this photo).
a backlit sun-pocalypse of cloud
I agree. At the same time, they are hard to capture well because of the contrast – the highlights can really wash out completely. This is why I sometimes like to drop all of the light away which turns the highlights into a feature in their own right.