Python has the same amount of nightmare. Maybe even more. You can add static class and instance accessors at runtime, it supports full monkey patching just like Ruby does. You can meta program modules, classes, objects, you can decorate classes and functions, declare functions and lambdas anywhere. "compilers" usually disallow monkey business and compile only a subset.

While my (half finished, buggy) Ruby compiler is definitely a subset, it allows the monkey business. There are ways to do it reasonably, but making it fast gets a lot harder when you do...