"Well, when you do something like Rocky which is indefinable somehow, it always becomes difficult to lose that"

This quote by Richard O'Brien talks to the problem of carrying on from an effective job. The success of Rocky was "indefinable" in some way, implying that it was hard to take into words what made it so effective. This makes it challenging for O'Brien to proceed from the task, as it was so effective and unique that it is difficult to reproduce. It is a pointer that success is not always simple to reproduce, and that it can be difficult to carry on from an effective task. O'Brien is likely referring to the trouble of finding a brand-new task that can match the success of Rocky, and the challenge of trying to recreate the very same level of success. This quote speaks with the problem of attempting to reproduce success, and the difficulty of proceeding from a successful project.