Back if the years when I was in the Army, I remember a particularly crusty senior NCO who used to say "I don't have to stick my hand up a cow's arse to feel a steak, I'll take the butcher's word for it". I'm not really sure what the context was for such a statement but he seemed to say it often enough that I remembered it. Regardless, it's a statement that I disagree with.
The Royal Society is a haven for scientographers and I'm willing to bet is the nerdiest place on the planet short of a sharpening forum. That being said, the Royal Society has a motto that I can truly get behind. Nullius in verba (Take nobody's word for it) meaning simply that you should be trying things for yourself and not taking other's reporting as the truth.
We are fortunate in today's world that we have tons of resources on almost any subject at our fingertips - modern day rabbit holes really. The problem with all that information is that we tend to spend too much time reading and studying and not enough time trying. Grain direction is a fine example. You can read all you want about grain direction or you can simply plane a board one way and then the other and see how it goes. You'll learn about tear-out and grain direction much faster by conducting your own experiments.
There are many of us creating articles and videos for you to peruse but I would recommend that you read and watch, then head to the bench and give things a try. There have been many times that I have read something that challenges my own experience and it's easiest to dismiss these views as being incorrect and continue living an insular existence. However, If you want to grow as a woodworker, I say head to the shop and give it try. What do you have to lose? You may discover a new or more effective way to do things.
You can do the same old thing, the same old way and get the same old results. Or you can test out something new, expand your knowledge and discover techniques you've never tried before. Moss never grows on a rolling stone.
In order to understand, you must do. - V