Much of today's home and office furniture have an assembly line look and feel. Uniformity has replaced beauty and craftsmanship. But have no fear, there are still some old school wood workers left, preferring to work with centuries old methodology, creating fine joinery such as mortise and tenon and dovetail joints, the hallmark of a true wood working artist.
I prefer to work by hand, using some power tools to save labor, but always making the final adjustments by hand. That includes the initial process of taking rough cut lumber, and milling it flat, straight, and square.
The milling process is what happens before the project can really start. Rough sawn from a tree, lumber needs to be perfectly flat and square on all six sides. That means every surface of a board needs to be "milled" straight, before sizing and joinery can begin.