What exactly is critical listening? Who does it?

I'm supposed to listen to every single instrument within a mixture of instruments. And somehow evaluate every aspect of what I'm listening to and somehow all this is critical listening.

This is supposed to bring enjoyment?

I'm just listening for the Quality of what I'm listening to with all the instruments playing and how good they sound hopefully. 

And I'm tired of answering that I'm not a robot all the time. That's being critical.