How do I know if all my optimizing actually made things better?

You can optimize anything to the decimal, and now you are wondering whether all that precision actually made things better. That is an honest and important question. Efficiency is easy to measure. Better is harder, and the fact that you feel the difference says something good about you. Faster and cheaper are not always the same as better for the people involved. Sometimes optimizing frees people up, and sometimes it just squeezes them tighter. You cannot know which from the numbers alone. But you can know it by looking at what your work left behind for real people. Pick one process you improved and ask a different question about it: did it make someone's day lighter, or only the output higher? If the answer troubles you, that is useful. It means you can start optimizing for something more than the decimal. The question is not a dead end. It is a better compass.