There are many things that can get attached to an idea or experience. I presume the more precious or particular the key advice, the more likely you are dealing with a barnacle that needs scraping off the hull of your given ship of life.. or a consultant hunting for someone to bill. Like this mystic wisdom about pouring your beer:
There’s more to pouring a beer than you may think. Pouring a beer improperly can pollute wonderful aromas, cause an improper release of CO2, and hinder the flavors of the beer. If you want your beer to fulfill its potential, consider this advice...You want to cock the glass a certain way depending on the style of beer. If the beer is highly carbonated, tilt the glass at a 45 degree angle and start pouring down the side. Wait until a third of the pour you want is in the glass, then tilt the glass upright and pour in the center. If the beer is lower in carbonation, start pouring downwards into the center of the glass earlier. A head the width of two fingers is a good rule of thumb for what you are looking for, Deman says.
I have never been particularly anal about how to pour a beer but even I would not look for a two inch head on a low carbonation style like mild. You'd drive the life out of it. But no doubt I've been a lifetime beer polluter and had no idea. Better rule of thumb: do what you like when you pour your beer and it probably works for you.