"works great" doesn't necessarily exclude "it's a stupid thing to do". I wonder how things like concurrency are expected to work, if no single line of code can

"works great" doesn't necessarily exclude "it's a stupid thing to do". I wonder how things like concurrency are expected to work, if no single line of code can be sure that things it expects will exist at runtime. Or maybe exists every 5 seconds for 3 seconds. It is an optimization nightmare (proven by the abhorrent performance Ruby exhibits). Even the Ruby "developers" have understood that monkey-patching is bad and decided to do something against it.