To me, casual listening is plopping down in front of an unfamiliar system, listening to some unfamiliar music. And you're really not listening for anything in particular, maybe you're just taking a breather.
Critical listening would be listening to familiar music on a hopefully somewhat familiar system, listening for how a component handles specific nuances that you find, well..., critical.
Critical listening would be listening to familiar music on a hopefully somewhat familiar system, listening for how a component handles specific nuances that you find, well..., critical.