why is it so difficult to undestand spoken English while learning it?

We sometimes have difficulties to understand spoken English in real usage. The classroom scenario tends to be an approximation from reality, a simulation of a series of situations where the teacher strives to get the best from the student and naturally, in this process, ends up grading down/up his(her) language. The teachers out there will most certainly understand this dilema... Either one speaks down the natural level to "help" the learners getting the idea that has proven difficult to convey or even one tries to force an unnatural speech pace to push the learner into fast traking the learning process. One way or the other, the learner who normally isn't exposed to spoken English finds himself/herself in a learning environment where real and quality exposure to the languge is scarse. Here I put this topic up to discission. What are your biggest challenges as a teacher, as a learner?? Leave a comment and  let's share some ideas on this very relevant matter...