Most rooms don’t need acoustical treatment.

Hear, hear MC. Absolutely right.

And even acousticians and psycho-acousticians admit there's much they don't know or can't explain. But this is true in every field, including the ones that collectively put men on the moon. 

Mofojo is right.  We do know how a car works.  On the other hand, we don't know why someone prefers a blue one to a red one, or a Camry to a Prius or why anyone  likes the Fiat 500.  (Well, maybe in some cases we do--like why I prefer my 88 Volvo wagon to anything built in the last twenty years that would cost me 30 or 40x as much).

You wouldn’t happen to have a blue 88 Volvo Wagon and live in West Mi would you? 

Room treatment can be tricky. Unless one can  determine what and where specific (!) problems are occurring and apply treatments to treat those specific problems at those specific locations, one might make things worse.

False. Panels can help greatly, even in cluttered rooms.