You know, the most counterintuitive lesson I've learned is that oversizing servo motors can actually cause more problems than it solves! Conventional wisdom tells us to add big safety margins - maybe 50-100% extra torque capacity and keep inertia ratios super low (like 10:1 or less). But in real applications, I've seen oversized motors create vibration and resonance issues that undersized motors wouldn't. Here's what's surprising: A motor that's too powerful for the load can actually make the system less stable. The higher torque-to-inertia ratio creates a stiffer system that's more prone to exciting mechanical resonances. I've worked on applications where we followed the textbook rules, sized up significantly, and ended up with chatter and vibration problems that required expensive vibration suppression controls. Another counterintuitive finding: Sometimes a slightly higher inertia ratio (say 15:1 or even 20:1) with proper tuning can actually give you smoother motion than an ultra-low ratio. The system has more 'give' and can absorb disturbances better. The key is understanding your specific application's dynamics rather than blindly following general rules. The real lesson? Don't just chase torque numbers or obsess over inertia ratios. Consider the complete system dynamics, including mechanical compliance, resonance frequencies, and actual motion profiles. Sometimes the 'safe' oversized motor creates problems that a properly sized motor wouldn't have. It's about finding the Goldilocks zone - not too big, not too small, but just right for your specific application.