u/Creative-Aspect-35

I'm applying to be a barback at an ale house where the barbacks are also basically bartenders, I'm doing research on properly pouring beers, and this is a random thought I had. Every time I've had a guinness, it tastes really good for the first few sips, like dark chocolate or black coffee, but by the halfway point it tastes like mud from a boot and despair. Of course, the few times I've had it were straight from the can, or on draft but not in a guinness glass, and never with the two part pour. Yes, I am in America. And I'm just wondering, does the two part pour make the flavor more consistent, or is it just for texture and theatrics? Am I missing out on a magical experience by no one doing it right?