I had a professor in college who taught several interesting technology classes, and one particular course was aimed at examining how computers are viewed and used in modern society. A prevailing topic of the course was the idea of how we put way too much credit into data and information created by computers and how frustrating computer errors can be largely attributed to the owner. My professor would point out that computers only do what we tell them to, meaning that the output that we get from them is the result of the input we humans give them.
You aren't a real designer until you've stared at a progress bar that's trickling along like sand down an hour glass. Waiting on renders can be agonizing, but sometimes it's our own fault. You should have noticed in the previous chapters that our scenes are becoming more complex with things like lights, shadows, materials, reflections, and transparency. The combination of these elements has caused your render previews to take far longer...