Each of the performance-enhancing suggestions we've explored so far has been primarily centered on reducing resource costs and avoiding frame rate issues. However, at its most fundamental level, seeking peak performance means improving the user experience. This is because every frame rate hiccup, every crash, and every system requirement that is too costly for a given market ultimately detracts from the quality of the product. Physics engines are a unique category of subsystems whose behavior and consistency contributes a significant factor toward product quality. Spending the time to improve their behavior is often worth the cost.
If important collision events get missed, the game freezes while it calculates a complex physics event, or the player falls through the floor, these scenarios have an obvious and significant negative impact on the quality of gameplay...