I worked with a guy who felt a burning need to use a certain JS functional utility library for literally everything. He would even use the library to access properties of objects instead of using JS's built in dot operator. This led to a lot of over-engineering on the micro level, although he had good practices on the macro level. The project was well thought out, but open any file and you'd see a bunch of this library's fanciest functional tricks.

I found it pretty bizarre. My guess was that he simply applied a different standard to code than most other people. Instead of preferring simple and obvious code, there was some other arbitrary criteria of cleverness he was looking for. This guy was very experienced as well. I think it may just have been boredom.