No polka dots
Polka dots were a decorative pattern known to Federation culture.
In 2372, while setting up a modular shelter on the planet soon to be christened New Earth, Chakotay and Kathryn Janeway talked about how Starfleet might have come up with something more cheerful for the module than beige or grey. Janeway suggested polka dots, though Chakotay was thinking more in the direction of pinstripes, possibly blue and green. (VOY: "Resolutions")