BTW, I often shorthand this as, "I'm not so much better [at optimization] as I am more stubborn."
The number of times I've gone in looking for 10%, backed out a bit and rearranged the code first to find 25%, better maintainability, and space for a feature that marketing has been bitching about for three years and development keeps insisting we cannot do in any reasonable amount of time? Probably averages out to at least three times per employer, which is a good number of miracles to perform.