[I can't find where else to put this in the blogki - but I think it belongs somewhere else.]
In a Popular Mechanics article
by Jamie Hyneman about the role of CAD in engineering:
To my way of thinking, an engineer's work is better if he has a foundation of hands-on experience. If he has memories of his own blood smeared on his tools, his approach to a mechanical problem will be different than if most of his insights arise while sitting in front of a computer.
Let's look at a staple of home-repair toolboxes: the pipe wrench. You just know it was designed by a guy who needed to get a job done in close quarters, and it was based on bleeding knuckles. The jaw is at 90 degrees to the handle, which is unlike any standard wrench. The heft of the tool, the rounded shapes of the pieces—all of these features were informed by users with years of experience in the field. And there's a great deal of slop—loose tolerances of all the moving parts—so that the wrench still works with rust, dirt and gunk all over it. The slop also means that the more torque you apply, the more the components shift, and the tighter the jaws bite into the pipe. Sometimes slop is our friend, but I've never seen it on a pull-down menu.