Why-is-stained-wood-that-is-done-professionally-so-smooth-and-practically-glossy-When-done-at-home-the-wood-still-feels-like-the-same-rough-wood-before-and-after

While waiting for my first kit to arrive, I stumbled on the above question on Quora. Some good tips in the longest answer. Not sure if they all apply to finishing a guitar, but there is info regarding different sanding directions that I didn't know before.