It's the lack of distinctive features. Detail is just hearing what you want to hear. If your expectations are broad and balanced (Ie, not just honing in on what helps you hear the singer's fart at 1:37 the best) then to hear the proper detail you want a smooth response with rises in the right areas (ear gain) and no big spikes or elevated regions that mask detail in adjacent regions.

But if you are hung up on the singer's fart then you are listening for a distinctive elevation in whatever frequency region helps you hear that at the expense of other details.