  In physics we encounter particles in one of two ways. Either as fundamental
constituents of the theory or as emergent excitations. These two ways differ by
how the particle relates to the background. It either sits on the background,
or it is an excitation of the background. We argue that by choosing the former
to construct our fundamental theories we have made a costly mistake. Instead we
should think of particles as excitations of a background. We show that this
point of view sheds new light on the cosmological constant problem and even
leads to observable consequences by giving a natural explanation for the
appearance of MOND-like behavior. In this context it also becomes clear why
there are numerical coincidences between the MOND acceleration parameter, the
cosmological constant and the Hubble parameter.
