Fully agree. About 40,000 eons ago I wrote a Forth compiler in ZX81 basic. It went from taking 19 seconds to print 1000 numbers on the screen to instantly. I also learned a great lesson: I looked at the machine code it generated (it had a pinhole optimizer because the output was PUSH HL, PUSH DE, POP DE, POP HL everywhere), and I thought it was perfection - impossible to improve. The day later I came back and made it much faster.