You try to make the walls look nice by coating them with your favorite shade of yellow. Unfortunately, whether it's a ladder you need to change a light bulb or a set of foldable chairs to accommodate extra guests, something's bound to scuff that wall eventually. Of course, that black streak just screams out against your beautiful buttercup yellow.
You can easily remove scuff marks from painted walls by scrubbing the scuffs with old-fashioned toothpaste (not the gel variety that's so common today, but the kind your grandparents kept in their medicine cabinet) and an old, soft-bristled toothbrush. The marks will come right off without you having to break open the paint can for a touch-up.