But there is another scenario and that is, maybe the man made structure can complement the composition and be the reason for taking a shot. Specifically, I see this potential in water reflections that include a bird or another type of animal. For instance, the shot above of the Portuguese man-o-war was taken on Biscayne Bay. As a tan canoe passed by, I saw this as an opportunity to photograph it with the boat's reflection offering a complementary color to the blue.
On Biscayne Bay, there is a location where condominium high rises reflect on the water. This area also happens to be where birds, especially great white egrets, feed during the low end of the tide. While I prefer that those condos were not there, they do give off some colorful reflections. Instead of seeing these reflections as "noise" to be avoided, I attempt to use them to frame a bird and add some color to the composition, as seen in the two photos below.
On Florida Bay near the Flamingo marina, the large pink visitor center building is quite a distraction along the shoreline of the bay. However, sometimes its reflection fills a significant part of the water where birds congregate. The reflection paints a pastel scene that is quite pleasing. So I purposely looked for an image that would include it. This shot of a willet might otherwise be extra boring.
At home, there is a small pond that is surrounded by condo buildings and fences. During the right time of day, they reflect beautiful colors onto the water. These reflections can make an uninteresting image of a bird more eye-catching.
On my patio, a spiny orbweaver spider made its web. Fortunately, the building to which the spider's web was attached, gave it a beautiful background to this image.
Of course, colors can be pleasing and complementary from any source. Nature provides many colors and when possible, we try to capitalize on them when composing a shot. Not only in reflections, but also as background. Here are two images where red from a poinciana tree reflects in the water and another where the red background is a bougainvillea vine. For both these shots, had I positioned myself slightly away from where I took the image, the colors would not have been in the frame.
When shooting in a busy location, play around with the composition (shoot lower or higher, move to the right or left, zoom in, use a shallow depth of field, etc) and get the colors where you want them. Instead of avoiding man made structures or busy backgrounds, try to use them to the advantage of your image.