So here's what I know now, and what painting taught me. There are times where you want high contrast -- a high value white against a low value dark, or vice versa. You even save that high contrast for the focal point of your painting; every painter has heard the phrase: "Save your darkest dark and your whitest white for the place you want the viewer's eye to go." In a portrait, that place is often the pupil and the reflected light.
Now what I did wrong in both the kitchen here and the cottage bathroom was to choose a light floor. A pristine canvas, so to speak, for any spot, spider or smooshed blueberry. Today the kitchen floor looked so much like an abstract painting that I really had no choice but to get down and clean it. But the minute it was clean, it turned right back into an empty canvas, daring life to slap paint on it. Double-dog-daring it.
Smart people put down mid-tone floors that have a variety of related tones. If I were to be allowed to choose another floor I would do that. Hope you're reading this, dear.