Woodworking was part of my first 3 years of high school, but it was mainly about learning safety and tool usage and not planning, estimating, selecting or purchasing timber.
These days I only want to go to the lumberyard once for a project. Learnt the hard way on my first project that you need to take the time to carefully select the timber - checking straightness, matching grain and also colour before I started. Major hassle and waste of time to have to go back to swap boards.
Sure enough, several had cracks at the ends, knots in poor places, and other things that, had I bought it, would have caused me trouble.
I can be a naive person in that I assume good faith. I would never knowingly sell something poor quality to someone else. I had assumed because I was being sold it, it was okay.
I know about wood quality and I have deliberately bought higher and lower grade wood. But even so, quality varies greatly.