Just to find the three primary colors, Red, Yellow, and Blue, all on the same wall is fortunate enough. But to make it work so well as an incongruous "romantic" encounter takes it far beyond just its lovely form. And there are two levels of incongruity going on here as well. Scale, of course is one of them. Huge woman, small man. But there is another incongruity nested at the core of this image. As you and others have already implied, she seems to be seducing him. Will he pay his quarter for a half hour of colorful pleasure? Stay tuned.
Beautiful colors and composition. You captured the onlooker at just the right moment. It's a shame, though, he has to pay the meter just to stop and look.
