CATCH – 22

A catch-22 is a paradoxical situation from which an individual cannot escape because of contradictory rules.

Eg: To apply for this job, you would have to be insane; but if you are insane, you are unacceptable for the job.

- thanks Wikipedia!

It's so easy to fall into a catch 22 situation during metcons. In your head you need to complete it with the Rx weights/reps/movements to get better.  But if you're not strong/skilled/conditioned enough, you don't get the correct stimulus to improve optimally, as your power output is down due to over-frequent resting, your technique suffers due to excessive load, or skill demand, and you also risk more CNS fatigue, frustration and injury.

So to some degree, the more you try to go Rx, the less chance you have of getting better.....

However, those who have the capacity to handle Rx efforts, are able to generate the high levels of output and intensity that the workout was designed to elicit, thus getting the desired adaptation and thus better able to handle future, tougher workouts.

Every workout has an intent behind it.  Try to meet that intent, and you'll avoid a catch 22.