Actually, I've had a different experience with cable mess. Last month, a system wouldn't boot even with perfect cable routing. It was a bad power supply, not the cables. @loganthompson, those nests you mentioned can be annoying, but they don't always cause post errors. I find that most no-post calls are from dead parts or loose RAM. Neat cables help, but they're not the biggest fix for boot problems.
Agree it's a universal tech life problem. I've spent whole afternoons untangling nests that seem to grow on their own. What's your go-to method for keeping them under control?