"- Reading and, in general, understanding Rails is horribly difficult, since it's no design and layers upon layers of magic. Very often you will find 5-7 layers of functions delegating the work deeper and deeper in, until you arrive to a completely undocumented internal function that in turn splits the work to three other, unrelated internal functions. Given that each of those 10 functions takes a hash called "options", each layer altering it subtly, but none having the complete picture, and that 9 times out of 10 that hash is not documented on any level, figuring out what your choices are is pure hell. It's made even more fun by the fact that different parts of Rails are accessible at various points of handling the request, and you can't just jump in and poke things from the console, since it won't have 99% of the things that only magically spring to life once a request is live. "
Methods do really nest pretty deeply sometimes. And since all of ruby's classes are open, people just add stuff by hacking things together. It's pretty much impossible sometimes knowing where a particular method is in the codebase.