Beauty is in the eye of the beholder (thankfully for people who are ugly). With that caveat in mind, I will hazard a pick: a recycling warehouse on the NS in Springfield, VA. One of the doors looks as though a forklift inside has hit it and it protrudes outward with recycling trash oozing onto the spur. It actually might be fun to model for those who like junk yards, but it tends to be more an eyesore. Junk yards are a bit more fascinating to me and obviously to many others (hence the popular TV show titled: Junkyard Wars).
The other element is that on smaller layouts, warehouses take up a lot of real estate unless they are selectively compressed.
Real railroads, of course, take an entirely different view. They could generally care less about aesthetics (often even their train aesthetics). They instead are more concerned with industries that generate steady streams of revenue, preferrably in large quantities and in key locations of density that don’t require long-distance switching.
I guess you’re right about ‘worse’ being relative. I equate ‘worst’ with hardest for me to model. Larger industries would be harder - the oil refinery you mentioned, steel mills - I actually think a scrap yard would be relatively easier to model…
you could combine industry and trains by making a locomotive rebuilding factory where they refurbish and overhaul locomotives. It is also an industry which requires a lot of goods and trainmovements (locomotives to overhaul, paint, dieseloil, parts, labour and scrap) and it’s something essential for the layout…
A rendering plant complete with smells. At one time I used to pass one on my way to work when I worked in S. Baltimore. On a warm summer day when a “fresh” delivery just came in you gagged withing a 1/4 mile of the place.
As my forum name suggests, I like passenger trains. I very much dislike every industry that goes with freight trains. The traditional log loaders, cattle cars, cranes, coal towers and the lot hold no interest to me. The noise these accessories make is enough to make your head pop as well. I did have a gateman one time and a newspaper stand with the dog that runs around but the noise made me sell them on eBay.
