Why? There always seem to be obstructions or telephone lines in the way of my promising cloud pictures. Of course, there are plenty of opportunities elsewhere. And on occasion there is a sunrise or sunset to assist. In this instance the early morning sunrise picture was modified by blurring from the rain on my window. The effect is sometimes sought via a lens filter. In this case my window provided the filter blur for free.
There’s nothing special in the technique or advice. Carry a camera. Use it. And do not hesitate to shoot thru glass be it car or home. I guess there is not much to be said for telephone lines and traffic. I would prefer to always avoid a traffic jam. Ha ha. I have a camera on my desk. I usually have one on the dashboard of the car.