Have you ever found yourself sitting by the side of a river, watching large ships passing by? You probably have, and otherwise you will some day. Now, have you ever found yourself sitting by the side of the highway, watching trucks passing by? Unless your car broke down, you probably haven’t. Actually that is quite strange. In essence, you would be watching the exact same thing. Goods being transported from one place to another. What is it that make ships more interesting to look at? We figured out a couple of reasons, while we were sitting by the side of the river (this is not true, but makes the story better).
The magnitude. Ships are huge when compared with most other modes of transport. River barges are smaller than seagoing ships, but they still have a considerable magnitude. People are generally amazed by large things. I guess there is a relation between how many times things are larger than you are, and the amount of amazement. No, I am not giving you a formula. But everyone probably has a memory of something in their youth, which they thought was really big. I was once fooled by a Spanish lighthouse, that I saw for the last time when I was 8 years old. At age 30 it turned out to be quite small.
The exposure to the elements. Ships navigate on water. And, although mankind has done a lot of work to regulate rivers, it is still water. It has a natural current you have to cope with; there are times of extreme drought and times of extreme rainfall that make rivers unnavigable; there are natural curves and narrows that make navigation difficult, for example at the Loreley (Rhine). Ships give you a sense of nostalgia, of the battle against the elements.
Less is more. It is simple. The Rhine is very busy with traffic, but it will never look as busy as a highway. You have plenty of time to look at individual ships, because they go slowly and it takes a while before the next one passes by. The event of seeing a ship passing by on a river is more unique than seeing a truck passing by on a highway. This uniqueness is being underlined by ships having names.
These are just some thought from by the side of the river. If anyone has figured out other reasons for ships being nicer to watch than trucks, let me know. And surely let me know if you like trucks better than ships. If you dare.