I once went into a project where the runtime for a complex financial calculation (as complex as it can be) was 8 to 10 hers. In 2 weeks it was 37 seconds and wo

I once went into a project where the runtime for a complex financial calculation (as complex as it can be) was 8 to 10 hers. In 2 weeks it was 37 seconds and working perfectly. When the CFO took me for dinner, I told him that 90% of the work was the old implementation, which set the right concepts, and I merely did an optimisation. Many times, the first take is not optimal, but I always try to appreciate the input I get even from suboptimal implementations.