For a minor example, recently I was building a representation of a rectangular tiled game board, and after fighting with the stdlib and lists for a while, found I could just, out-of-the-box and with a bare minimum of effort, build a directed graph, with built in pathfinding and access.
What you get for free is phenomenal
You'll see quite a few people commenting in this thread (including me) who have spent something like 10-15+ years working with OO languages, we've seen the ugly sides of mutability, dependency spaghetti, holding onto state too tightly, too much coupling between classes, and the like; not to mention the difficulty with concurrency in a world where anything can mutate global state (such as class definitions).