Do Audio Hobbyists Commonly Fail to Fully Utilize Their Systems?

This question is polite way of asking: How many of us spend big bucks to secure the best sound we can, only to misuse or under use our equipment? IF my personal experience is anything to go by (probably not typical) many times I've done something purely ignorant which resulted in an otherwise decent system failing to perform as it could if well connected? My error in my SVS sub settings is a perfect example. This morning the timbre and soundstage is unlike I've ever heard from this chair. For a year at least I had two filters fighting each other squashing my tunes! Audiogon forums are often assessed to cure perceived problems by members however, what one doesn't know CAN harm you! (your sound that is).My short list of crazy stupid isn't by any means limited to the subwoofer setting error. A short list includes wrong tubes in wrong places, modem and router WAY TOO close to amp, speakers overly toed`in, and the list goes on...Its probably impossible to believe but apparently some of us need a "systems check up"! Wishful thinking I suppose but you know there's others who have invested hundreds if not thousands only to produce B~ sound.  Check list? "FIND WEAKEST LINK HOTLINE"? Ideas?