To be specific, it's the lack of typing that makes large code bases in Python, Ruby, and especially JavaScript a huge pain compared to Java. It makes debugging much more difficult. Thankfully this is being fixed with stuff like Typescript and similar projects for both Python and Ruby.

Some people may argue, "but documentation would make this an non-issue". Guarantees built-in to the platform itself are more reliable than human aspirations, or automatic memory management as a feature wouldn't have gotten popular.