In real life, everything is not perfectly straight up and down. By this I mean, look at a lot of road signs, street signs, and telephone or power poles. Some lean, either from being old, under too much tension, lean from years of high wind, or in the case of street signs and road signs, from an occasional bump from a car or truck, or perhaps kids swinging from the signs. This we can simulate on our model railroads as well. Everything is not perfectly straight, and should be reflected in our layouts.
Another factor to simulate is trash. Railroads and their environs are not clean places, especially in industrial areas. This holds true whether 50 years ago or today. Don with IndustrialModels and Lance Mindheim demonstrate this the best I think. Take a look at their work and websites, and you’ll see what I mean. We can also simulate this, and should, with weeded side tracks, garbage, debris, etc. along our tracks, yards and such.
The following two photos demonstrate that all is not straight in the real world. I think you can see the pole lean in the one photo below!